<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2021 Workiva-->
<!--r:e0ca318f-3884-42e6-a64c-8779d462d73a,g:75807743-642d-4c80-8d38-07220e8d8bcd-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.amgen.com/role/Coverpage" xlink:type="simple" xlink:href="amgn-20201231.xsd#Coverpage"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/Coverpage" xlink:type="extended" id="i3cf690233cc948f4b8f442ae48eef617_Coverpage">
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_c68be916-580b-43cd-84c5-eaf96a2e423c" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_DocumentType_c68be916-580b-43cd-84c5-eaf96a2e423c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentAnnualReport_6e3c80db-9557-4a4c-8b2e-78af588f7688" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_DocumentAnnualReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_DocumentAnnualReport_6e3c80db-9557-4a4c-8b2e-78af588f7688" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_6874bc64-572a-4c7e-8ae0-310fd5a63672" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_DocumentPeriodEndDate_6874bc64-572a-4c7e-8ae0-310fd5a63672" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentTransitionReport_bb20a3b5-7aae-4ea4-aed9-9fd73fa91c58" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_DocumentTransitionReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_DocumentTransitionReport_bb20a3b5-7aae-4ea4-aed9-9fd73fa91c58" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_ca3d82e4-3842-44f0-9fc0-3daa9ed82f38" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_EntityFileNumber_ca3d82e4-3842-44f0-9fc0-3daa9ed82f38" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_bbd3543e-6345-418b-a9d0-65ab41265958" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_EntityRegistrantName_bbd3543e-6345-418b-a9d0-65ab41265958" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_037c3888-7196-421f-bd24-85784f9636e0" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_EntityIncorporationStateCountryCode_037c3888-7196-421f-bd24-85784f9636e0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_3acc66a6-c50b-45b0-8598-60a608993a8a" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_EntityTaxIdentificationNumber_3acc66a6-c50b-45b0-8598-60a608993a8a" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_73b57b2a-a511-4cf3-ad69-56214a3d09f0" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_EntityAddressAddressLine1_73b57b2a-a511-4cf3-ad69-56214a3d09f0" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_323586b2-9579-4964-a1e7-3c111b35ed21" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_EntityAddressCityOrTown_323586b2-9579-4964-a1e7-3c111b35ed21" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_35317354-b2b7-48fa-b5eb-794e312137ea" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_EntityAddressStateOrProvince_35317354-b2b7-48fa-b5eb-794e312137ea" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_89d98085-9e73-40ba-af78-437eef9abd61" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_EntityAddressPostalZipCode_89d98085-9e73-40ba-af78-437eef9abd61" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_ec47f718-e48c-4281-a60e-516d4b53af12" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_CityAreaCode_ec47f718-e48c-4281-a60e-516d4b53af12" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_12496e55-d068-4dbf-af93-921729d2677a" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_LocalPhoneNumber_12496e55-d068-4dbf-af93-921729d2677a" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_d996fa65-6ede-4277-aa90-4d1a37d38311" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_Security12bTitle_d996fa65-6ede-4277-aa90-4d1a37d38311" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_fd9b758a-4ea1-4e68-a125-be3e15b3a8e9" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_TradingSymbol_fd9b758a-4ea1-4e68-a125-be3e15b3a8e9" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_8f705f45-3295-4c8d-9ac7-32536090567d" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_SecurityExchangeName_8f705f45-3295-4c8d-9ac7-32536090567d" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityWellKnownSeasonedIssuer_9aba663e-2480-44bc-a51b-c316c3281708" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityWellKnownSeasonedIssuer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_EntityWellKnownSeasonedIssuer_9aba663e-2480-44bc-a51b-c316c3281708" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityVoluntaryFilers_ac4974a1-f64a-4df2-8834-601f48bd7b02" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityVoluntaryFilers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_EntityVoluntaryFilers_ac4974a1-f64a-4df2-8834-601f48bd7b02" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCurrentReportingStatus_0bc04c6f-7c87-40d5-9d7a-d4d08a545b14" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityCurrentReportingStatus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_EntityCurrentReportingStatus_0bc04c6f-7c87-40d5-9d7a-d4d08a545b14" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInteractiveDataCurrent_e7d60b5a-4c81-4901-abdd-b96289f7b1de" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityInteractiveDataCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_EntityInteractiveDataCurrent_e7d60b5a-4c81-4901-abdd-b96289f7b1de" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFilerCategory_eee5b9f1-26f5-4d38-96c6-08ecc998e015" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityFilerCategory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_EntityFilerCategory_eee5b9f1-26f5-4d38-96c6-08ecc998e015" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitySmallBusiness_1b065504-0a34-4f6e-bfea-df82f6d6cdec" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntitySmallBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_EntitySmallBusiness_1b065504-0a34-4f6e-bfea-df82f6d6cdec" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_c9b45a98-5e45-4ddb-a8bd-57adf8b50ce2" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_EntityEmergingGrowthCompany_c9b45a98-5e45-4ddb-a8bd-57adf8b50ce2" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_IcfrAuditorAttestationFlag_9fe32019-df76-499f-83fe-90bace5552a2" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_IcfrAuditorAttestationFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_IcfrAuditorAttestationFlag_9fe32019-df76-499f-83fe-90bace5552a2" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityShellCompany_4bb0421e-4c9e-44e3-8e46-c8ddb762e23a" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityShellCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_EntityShellCompany_4bb0421e-4c9e-44e3-8e46-c8ddb762e23a" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityPublicFloat_e85578ef-7c1d-4bb4-998b-16590db0c668" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityPublicFloat"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_EntityPublicFloat_e85578ef-7c1d-4bb4-998b-16590db0c668" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_094434fe-fea7-48cc-bca4-c2e78990296c" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityCommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_094434fe-fea7-48cc-bca4-c2e78990296c" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentsIncorporatedByReferenceTextBlock_ab80ff66-7fb8-4926-a478-e985135c558e" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_DocumentsIncorporatedByReferenceTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_DocumentsIncorporatedByReferenceTextBlock_ab80ff66-7fb8-4926-a478-e985135c558e" xlink:type="arc" order="28"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_1d32706c-9599-4580-a58c-03b6ca152086" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_EntityCentralIndexKey_1d32706c-9599-4580-a58c-03b6ca152086" xlink:type="arc" order="29"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_5157d6c5-8e11-488a-8c9e-996bf8afd991" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_AmendmentFlag_5157d6c5-8e11-488a-8c9e-996bf8afd991" xlink:type="arc" order="30"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalYearFocus_80e91f33-aa34-4cf2-8cb5-b220a0064e66" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_DocumentFiscalYearFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_DocumentFiscalYearFocus_80e91f33-aa34-4cf2-8cb5-b220a0064e66" xlink:type="arc" order="31"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalPeriodFocus_29291f5b-b357-44cb-8151-ce524a053958" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_DocumentFiscalPeriodFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_DocumentFiscalPeriodFocus_29291f5b-b357-44cb-8151-ce524a053958" xlink:type="arc" order="32"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate_a047e07b-6349-4c00-85e9-10de3a652250" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_CurrentFiscalYearEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_CurrentFiscalYearEndDate_a047e07b-6349-4c00-85e9-10de3a652250" xlink:type="arc" order="33"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitiesTable_2cde8740-593e-4b9c-911d-b3a0aff0ce39" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityInformationLineItems_63634280-6d6c-4fe1-9926-3caececec764" xlink:to="loc_dei_EntitiesTable_2cde8740-593e-4b9c-911d-b3a0aff0ce39" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_53a390ff-a435-4fc3-9721-a51397be1658" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_2cde8740-593e-4b9c-911d-b3a0aff0ce39" xlink:to="loc_us-gaap_StatementClassOfStockAxis_53a390ff-a435-4fc3-9721-a51397be1658" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_53a390ff-a435-4fc3-9721-a51397be1658_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_53a390ff-a435-4fc3-9721-a51397be1658" xlink:to="loc_us-gaap_ClassOfStockDomain_53a390ff-a435-4fc3-9721-a51397be1658_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_251d435a-ca54-49a2-ac64-dd7d426fed34" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_53a390ff-a435-4fc3-9721-a51397be1658" xlink:to="loc_us-gaap_ClassOfStockDomain_251d435a-ca54-49a2-ac64-dd7d426fed34" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_a370f04e-4d65-4791-9f49-837adf038c00" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_251d435a-ca54-49a2-ac64-dd7d426fed34" xlink:to="loc_us-gaap_CommonStockMember_a370f04e-4d65-4791-9f49-837adf038c00" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_A1.250SeniorNotesDue2022Member_bed0d9d2-bb7d-4379-878e-62e5345f09bb" xlink:href="amgn-20201231.xsd#amgn_A1.250SeniorNotesDue2022Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_251d435a-ca54-49a2-ac64-dd7d426fed34" xlink:to="loc_amgn_A1.250SeniorNotesDue2022Member_bed0d9d2-bb7d-4379-878e-62e5345f09bb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_A2.00SeniorNotesDue2026Member_7da707b9-8fa1-4178-ac20-c447c4fe42f7" xlink:href="amgn-20201231.xsd#amgn_A2.00SeniorNotesDue2026Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_251d435a-ca54-49a2-ac64-dd7d426fed34" xlink:to="loc_amgn_A2.00SeniorNotesDue2026Member_7da707b9-8fa1-4178-ac20-c447c4fe42f7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityListingsExchangeAxis_1f1b6c82-805f-4b48-b048-b4f61a6b78e3" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityListingsExchangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_2cde8740-593e-4b9c-911d-b3a0aff0ce39" xlink:to="loc_dei_EntityListingsExchangeAxis_1f1b6c82-805f-4b48-b048-b4f61a6b78e3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_ExchangeDomain_1f1b6c82-805f-4b48-b048-b4f61a6b78e3_default" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_ExchangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_EntityListingsExchangeAxis_1f1b6c82-805f-4b48-b048-b4f61a6b78e3" xlink:to="loc_dei_ExchangeDomain_1f1b6c82-805f-4b48-b048-b4f61a6b78e3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_ExchangeDomain_21bd745e-07b8-43a2-af8c-2b6a4852ae7a" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_ExchangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_EntityListingsExchangeAxis_1f1b6c82-805f-4b48-b048-b4f61a6b78e3" xlink:to="loc_dei_ExchangeDomain_21bd745e-07b8-43a2-af8c-2b6a4852ae7a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_exch_XNGS_b06f0057-1282-4c44-b12b-5f24bfd4c74e" xlink:href="https://xbrl.sec.gov/exch/2020/exch-2020-01-31.xsd#exch_XNGS"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_ExchangeDomain_21bd745e-07b8-43a2-af8c-2b6a4852ae7a" xlink:to="loc_exch_XNGS_b06f0057-1282-4c44-b12b-5f24bfd4c74e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_exch_XNYS_aa7ea2dc-d206-43d2-9415-54c8117e5e33" xlink:href="https://xbrl.sec.gov/exch/2020/exch-2020-01-31.xsd#exch_XNYS"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_ExchangeDomain_21bd745e-07b8-43a2-af8c-2b6a4852ae7a" xlink:to="loc_exch_XNYS_aa7ea2dc-d206-43d2-9415-54c8117e5e33" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/ConsolidatedStatementsofIncome" xlink:type="simple" xlink:href="amgn-20201231.xsd#ConsolidatedStatementsofIncome"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/ConsolidatedStatementsofIncome" xlink:type="extended" id="i578d27e08684475a95db2e1763cfef52_ConsolidatedStatementsofIncome">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_86185e27-a013-4387-b013-5ad5841260ba" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_988e58bc-21bb-438b-a9de-9daf6b328c87" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenuesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_86185e27-a013-4387-b013-5ad5841260ba" xlink:to="loc_us-gaap_RevenuesAbstract_988e58bc-21bb-438b-a9de-9daf6b328c87" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_5f9b0195-cd81-417f-9e77-d6ffb022bcac" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_988e58bc-21bb-438b-a9de-9daf6b328c87" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_5f9b0195-cd81-417f-9e77-d6ffb022bcac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_36596d40-6a65-4edc-9c42-165534b230f9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_988e58bc-21bb-438b-a9de-9daf6b328c87" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_36596d40-6a65-4edc-9c42-165534b230f9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_8d916f5e-ae7f-400c-a5be-320273be9fa0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_988e58bc-21bb-438b-a9de-9daf6b328c87" xlink:to="loc_us-gaap_Revenues_8d916f5e-ae7f-400c-a5be-320273be9fa0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpensesAbstract_9d56c423-674a-4f0a-a8ad-ffa2475e1a05" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CostsAndExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_86185e27-a013-4387-b013-5ad5841260ba" xlink:to="loc_us-gaap_CostsAndExpensesAbstract_9d56c423-674a-4f0a-a8ad-ffa2475e1a05" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_d3c6a8ff-fd6d-4ca0-a3cc-22306a15beed" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_9d56c423-674a-4f0a-a8ad-ffa2475e1a05" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_d3c6a8ff-fd6d-4ca0-a3cc-22306a15beed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseExcludingAcquiredInProcessCost_589ac90b-3a6a-4bc1-98e8-44e355bbf986" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ResearchAndDevelopmentExpenseExcludingAcquiredInProcessCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_9d56c423-674a-4f0a-a8ad-ffa2475e1a05" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseExcludingAcquiredInProcessCost_589ac90b-3a6a-4bc1-98e8-44e355bbf986" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_40f7a2e8-b8c3-4e25-8231-edb66a55dae5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_9d56c423-674a-4f0a-a8ad-ffa2475e1a05" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_40f7a2e8-b8c3-4e25-8231-edb66a55dae5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherGeneralExpense_4899cb2b-029d-49b9-89b6-98b0633dbe3c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherGeneralExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_9d56c423-674a-4f0a-a8ad-ffa2475e1a05" xlink:to="loc_us-gaap_OtherGeneralExpense_4899cb2b-029d-49b9-89b6-98b0633dbe3c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpenses_8e917e78-abd5-4a44-9e5e-5cbcdbcd59a2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CostsAndExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_9d56c423-674a-4f0a-a8ad-ffa2475e1a05" xlink:to="loc_us-gaap_CostsAndExpenses_8e917e78-abd5-4a44-9e5e-5cbcdbcd59a2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_d21b7c32-ff72-494c-8d2a-698b0003c1db" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_86185e27-a013-4387-b013-5ad5841260ba" xlink:to="loc_us-gaap_OperatingIncomeLoss_d21b7c32-ff72-494c-8d2a-698b0003c1db" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebt_55daeaff-ce57-4d92-aae5-79ffaecaaba5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_86185e27-a013-4387-b013-5ad5841260ba" xlink:to="loc_us-gaap_InterestExpenseDebt_55daeaff-ce57-4d92-aae5-79ffaecaaba5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_ed9fb0cb-f578-44a8-b9dd-2242dc084d83" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_86185e27-a013-4387-b013-5ad5841260ba" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_ed9fb0cb-f578-44a8-b9dd-2242dc084d83" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_f790091d-c965-4634-910b-79e0de603f0b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_86185e27-a013-4387-b013-5ad5841260ba" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_f790091d-c965-4634-910b-79e0de603f0b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_ad5d8e93-39b6-457a-9bba-8e1d830d9546" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_86185e27-a013-4387-b013-5ad5841260ba" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_ad5d8e93-39b6-457a-9bba-8e1d830d9546" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_a9c1db38-0615-4125-90cf-161c6deb665f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_86185e27-a013-4387-b013-5ad5841260ba" xlink:to="loc_us-gaap_NetIncomeLoss_a9c1db38-0615-4125-90cf-161c6deb665f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_1f69d4c2-3337-4da3-b089-8dc8bfcd6d65" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_86185e27-a013-4387-b013-5ad5841260ba" xlink:to="loc_us-gaap_EarningsPerShareAbstract_1f69d4c2-3337-4da3-b089-8dc8bfcd6d65" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_fce6bb92-1404-4d49-adae-1a51a91a9d16" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_1f69d4c2-3337-4da3-b089-8dc8bfcd6d65" xlink:to="loc_us-gaap_EarningsPerShareBasic_fce6bb92-1404-4d49-adae-1a51a91a9d16" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_62f38dd8-4e19-460e-8c2f-02e051ffc0e5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_1f69d4c2-3337-4da3-b089-8dc8bfcd6d65" xlink:to="loc_us-gaap_EarningsPerShareDiluted_62f38dd8-4e19-460e-8c2f-02e051ffc0e5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_aafba76a-848c-4a4b-a2fa-3c5fcad7bc17" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_86185e27-a013-4387-b013-5ad5841260ba" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_aafba76a-848c-4a4b-a2fa-3c5fcad7bc17" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_8e1d72e1-a0ce-47e5-b9e2-0c69496f4323" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_aafba76a-848c-4a4b-a2fa-3c5fcad7bc17" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_8e1d72e1-a0ce-47e5-b9e2-0c69496f4323" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_a9dfd8f3-1139-49db-bf4f-c55a15fa0c34" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_aafba76a-848c-4a4b-a2fa-3c5fcad7bc17" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_a9dfd8f3-1139-49db-bf4f-c55a15fa0c34" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_165b10b1-f2ad-4a11-a7cc-957e17244c24" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_86185e27-a013-4387-b013-5ad5841260ba" xlink:to="loc_us-gaap_StatementTable_165b10b1-f2ad-4a11-a7cc-957e17244c24" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_e16937d0-4fe3-49df-b365-69f4b151cdb6" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_165b10b1-f2ad-4a11-a7cc-957e17244c24" xlink:to="loc_srt_ProductOrServiceAxis_e16937d0-4fe3-49df-b365-69f4b151cdb6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_e16937d0-4fe3-49df-b365-69f4b151cdb6_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_e16937d0-4fe3-49df-b365-69f4b151cdb6" xlink:to="loc_srt_ProductsAndServicesDomain_e16937d0-4fe3-49df-b365-69f4b151cdb6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_c5eac7c3-be1f-4ede-91bc-30f1edd174ca" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_e16937d0-4fe3-49df-b365-69f4b151cdb6" xlink:to="loc_srt_ProductsAndServicesDomain_c5eac7c3-be1f-4ede-91bc-30f1edd174ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductMember_d5a746ba-2914-462f-9056-4b517e25a14a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_c5eac7c3-be1f-4ede-91bc-30f1edd174ca" xlink:to="loc_us-gaap_ProductMember_d5a746ba-2914-462f-9056-4b517e25a14a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductAndServiceOtherMember_6a6d9c16-e363-45b9-8c21-e187f9be10f5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProductAndServiceOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_c5eac7c3-be1f-4ede-91bc-30f1edd174ca" xlink:to="loc_us-gaap_ProductAndServiceOtherMember_6a6d9c16-e363-45b9-8c21-e187f9be10f5" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/ConsolidatedStatementsofComprehensiveIncome" xlink:type="simple" xlink:href="amgn-20201231.xsd#ConsolidatedStatementsofComprehensiveIncome"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/ConsolidatedStatementsofComprehensiveIncome" xlink:type="extended" id="ifda708d2c8ba4de5b5bacbcae448876b_ConsolidatedStatementsofComprehensiveIncome"/>
  <link:roleRef roleURI="http://www.amgen.com/role/ConsolidatedBalanceSheets" xlink:type="simple" xlink:href="amgn-20201231.xsd#ConsolidatedBalanceSheets"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/ConsolidatedBalanceSheets" xlink:type="extended" id="id5757d0df5ac47fb933dc23422a95f65_ConsolidatedBalanceSheets"/>
  <link:roleRef roleURI="http://www.amgen.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="simple" xlink:href="amgn-20201231.xsd#ConsolidatedBalanceSheetsParenthetical"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="extended" id="i239f1260751b4059a92aaee947699331_ConsolidatedBalanceSheetsParenthetical"/>
  <link:roleRef roleURI="http://www.amgen.com/role/ConsolidatedStatementsofStockholdersEquity" xlink:type="simple" xlink:href="amgn-20201231.xsd#ConsolidatedStatementsofStockholdersEquity"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/ConsolidatedStatementsofStockholdersEquity" xlink:type="extended" id="i5925335242154998a638d0bd6203df0a_ConsolidatedStatementsofStockholdersEquity">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_f4dc3b3c-cc9d-4ba2-8764-7099155bd116" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3380189a-1f3b-4e98-81f4-165e67624032" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_f4dc3b3c-cc9d-4ba2-8764-7099155bd116" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3380189a-1f3b-4e98-81f4-165e67624032" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_4bb823a2-b437-4f89-9b6b-569e14c67903" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3380189a-1f3b-4e98-81f4-165e67624032" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_4bb823a2-b437-4f89-9b6b-569e14c67903" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_3b495d77-b429-4dfe-b300-c05f31912fac" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3380189a-1f3b-4e98-81f4-165e67624032" xlink:to="loc_us-gaap_StockholdersEquity_3b495d77-b429-4dfe-b300-c05f31912fac" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_4ed0f28e-5c53-40e6-9170-f833ed62db0f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3380189a-1f3b-4e98-81f4-165e67624032" xlink:to="loc_us-gaap_NetIncomeLoss_4ed0f28e-5c53-40e6-9170-f833ed62db0f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_64c63667-4620-4b85-a671-5f74968c88a3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3380189a-1f3b-4e98-81f4-165e67624032" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_64c63667-4620-4b85-a671-5f74968c88a3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStockCash_b98806ed-e27f-4de8-ad4a-3d96267c803a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DividendsCommonStockCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3380189a-1f3b-4e98-81f4-165e67624032" xlink:to="loc_us-gaap_DividendsCommonStockCash_b98806ed-e27f-4de8-ad4a-3d96267c803a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_315f879a-e9ef-4187-9e37-e2617cac33cf" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3380189a-1f3b-4e98-81f4-165e67624032" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_315f879a-e9ef-4187-9e37-e2617cac33cf" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_1904cfeb-f1b3-4ec1-9a53-87d73e4decdc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3380189a-1f3b-4e98-81f4-165e67624032" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_1904cfeb-f1b3-4ec1-9a53-87d73e4decdc" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_ec5847b7-b68d-4937-9a45-bb7c35a9fb26" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3380189a-1f3b-4e98-81f4-165e67624032" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_ec5847b7-b68d-4937-9a45-bb7c35a9fb26" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentToAdditionalPaidInCapitalIncomeTaxEffectFromShareBasedCompensationNet_384d3327-c824-4e89-be2f-37ff5d799f40" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentToAdditionalPaidInCapitalIncomeTaxEffectFromShareBasedCompensationNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3380189a-1f3b-4e98-81f4-165e67624032" xlink:to="loc_us-gaap_AdjustmentToAdditionalPaidInCapitalIncomeTaxEffectFromShareBasedCompensationNet_384d3327-c824-4e89-be2f-37ff5d799f40" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_ef1b30f3-b338-4718-842c-b4c39a25297e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3380189a-1f3b-4e98-81f4-165e67624032" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_ef1b30f3-b338-4718-842c-b4c39a25297e" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_7d97461a-bcd7-4a47-95d2-45c7f7839689" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3380189a-1f3b-4e98-81f4-165e67624032" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_7d97461a-bcd7-4a47-95d2-45c7f7839689" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_592bb46a-cfd4-4439-9151-d98cd6c087dd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_ac484624-d61d-4277-8a90-187411357c36" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_04cbb08f-1d2f-4e13-b0b0-1d54e2636b8e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_f4dc3b3c-cc9d-4ba2-8764-7099155bd116" xlink:to="loc_us-gaap_StatementTable_04cbb08f-1d2f-4e13-b0b0-1d54e2636b8e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_6971ca3e-200d-4c8c-9172-3ce3fc677482" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_04cbb08f-1d2f-4e13-b0b0-1d54e2636b8e" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_6971ca3e-200d-4c8c-9172-3ce3fc677482" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_6971ca3e-200d-4c8c-9172-3ce3fc677482_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_6971ca3e-200d-4c8c-9172-3ce3fc677482" xlink:to="loc_us-gaap_EquityComponentDomain_6971ca3e-200d-4c8c-9172-3ce3fc677482_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_1af195b8-08c0-4ebe-aaf2-253e420ce6b6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_6971ca3e-200d-4c8c-9172-3ce3fc677482" xlink:to="loc_us-gaap_EquityComponentDomain_1af195b8-08c0-4ebe-aaf2-253e420ce6b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_59c00041-7ae9-4a93-90e1-6488006442af" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_1af195b8-08c0-4ebe-aaf2-253e420ce6b6" xlink:to="loc_us-gaap_CommonStockMember_59c00041-7ae9-4a93-90e1-6488006442af" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockIncludingAdditionalPaidInCapitalMember_579f5cb8-93a5-4bd7-a944-29e378e5ab02" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockIncludingAdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_1af195b8-08c0-4ebe-aaf2-253e420ce6b6" xlink:to="loc_us-gaap_CommonStockIncludingAdditionalPaidInCapitalMember_579f5cb8-93a5-4bd7-a944-29e378e5ab02" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_5de87f72-6792-4fa5-878d-d396c73dd5d9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_1af195b8-08c0-4ebe-aaf2-253e420ce6b6" xlink:to="loc_us-gaap_RetainedEarningsMember_5de87f72-6792-4fa5-878d-d396c73dd5d9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_dd4bba00-154a-43eb-9d44-ab8fe38fe69c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_1af195b8-08c0-4ebe-aaf2-253e420ce6b6" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_dd4bba00-154a-43eb-9d44-ab8fe38fe69c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_9d1c67ae-c2e5-4c3e-8c03-d14152f4cb10" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_04cbb08f-1d2f-4e13-b0b0-1d54e2636b8e" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_9d1c67ae-c2e5-4c3e-8c03-d14152f4cb10" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_9d1c67ae-c2e5-4c3e-8c03-d14152f4cb10_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_9d1c67ae-c2e5-4c3e-8c03-d14152f4cb10" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_9d1c67ae-c2e5-4c3e-8c03-d14152f4cb10_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_5230d4bf-a81d-4f2a-a5a3-586ebd999ce7" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_9d1c67ae-c2e5-4c3e-8c03-d14152f4cb10" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_5230d4bf-a81d-4f2a-a5a3-586ebd999ce7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_ac7478fe-c5fa-4918-985a-b425a41b269a" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_5230d4bf-a81d-4f2a-a5a3-586ebd999ce7" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_ac7478fe-c5fa-4918-985a-b425a41b269a" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/ConsolidatedStatementsofStockholdersEquityParenthetical" xlink:type="simple" xlink:href="amgn-20201231.xsd#ConsolidatedStatementsofStockholdersEquityParenthetical"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/ConsolidatedStatementsofStockholdersEquityParenthetical" xlink:type="extended" id="i582bbb34f204466fa0c794c383f44bae_ConsolidatedStatementsofStockholdersEquityParenthetical"/>
  <link:roleRef roleURI="http://www.amgen.com/role/ConsolidatedStatementsofCashFlows" xlink:type="simple" xlink:href="amgn-20201231.xsd#ConsolidatedStatementsofCashFlows"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/ConsolidatedStatementsofCashFlows" xlink:type="extended" id="id6bf6e1e29d242b28a1645cea6a32aa5_ConsolidatedStatementsofCashFlows"/>
  <link:roleRef roleURI="http://www.amgen.com/role/Summaryofsignificantaccountingpolicies" xlink:type="simple" xlink:href="amgn-20201231.xsd#Summaryofsignificantaccountingpolicies"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/Summaryofsignificantaccountingpolicies" xlink:type="extended" id="ic5bc1da1caf14d39af98d89d7cfae8ad_Summaryofsignificantaccountingpolicies"/>
  <link:roleRef roleURI="http://www.amgen.com/role/SummaryofsignificantaccountingpoliciesPolicies" xlink:type="simple" xlink:href="amgn-20201231.xsd#SummaryofsignificantaccountingpoliciesPolicies"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/SummaryofsignificantaccountingpoliciesPolicies" xlink:type="extended" id="i07ab0ed563af4386be7fe6c99bc925e2_SummaryofsignificantaccountingpoliciesPolicies"/>
  <link:roleRef roleURI="http://www.amgen.com/role/SummaryofsignificantaccountingpoliciesNarrativeDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#SummaryofsignificantaccountingpoliciesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/SummaryofsignificantaccountingpoliciesNarrativeDetails" xlink:type="extended" id="idaa41467da414fb48606c40e985109f3_SummaryofsignificantaccountingpoliciesNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_6001d63c-11b3-41ac-8e63-60fb08fad44d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfOperatingSegments_880ef71a-db84-40ee-90a0-9b971815912b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NumberOfOperatingSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_6001d63c-11b3-41ac-8e63-60fb08fad44d" xlink:to="loc_us-gaap_NumberOfOperatingSegments_880ef71a-db84-40ee-90a0-9b971815912b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_SalesDeductionsOnPriorPeriodSalesDueToChangeInEstimate_a84a7838-ccc9-4e1b-9b06-2cf0a6ae74f1" xlink:href="amgn-20201231.xsd#amgn_SalesDeductionsOnPriorPeriodSalesDueToChangeInEstimate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_6001d63c-11b3-41ac-8e63-60fb08fad44d" xlink:to="loc_amgn_SalesDeductionsOnPriorPeriodSalesDueToChangeInEstimate_a84a7838-ccc9-4e1b-9b06-2cf0a6ae74f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_SalesReturnProvisionsAsPercentageOfProductSales_a1fcbef6-ec07-46dd-9c0a-7b78e9f01ab0" xlink:href="amgn-20201231.xsd#amgn_SalesReturnProvisionsAsPercentageOfProductSales"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_6001d63c-11b3-41ac-8e63-60fb08fad44d" xlink:to="loc_amgn_SalesReturnProvisionsAsPercentageOfProductSales_a1fcbef6-ec07-46dd-9c0a-7b78e9f01ab0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdvertisingExpense_8e1ab004-9178-4a60-9667-145dfdacd7e0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdvertisingExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_6001d63c-11b3-41ac-8e63-60fb08fad44d" xlink:to="loc_us-gaap_AdvertisingExpense_8e1ab004-9178-4a60-9667-145dfdacd7e0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_RevenuePaymentArrangementTerm_a2fa4b7f-edcc-49e5-8d3d-23e0f3f7c9a5" xlink:href="amgn-20201231.xsd#amgn_RevenuePaymentArrangementTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_6001d63c-11b3-41ac-8e63-60fb08fad44d" xlink:to="loc_amgn_RevenuePaymentArrangementTerm_a2fa4b7f-edcc-49e5-8d3d-23e0f3f7c9a5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_5895ad53-48f5-41ef-910c-3615ef5e15e6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_6001d63c-11b3-41ac-8e63-60fb08fad44d" xlink:to="loc_us-gaap_OperatingLeaseLiability_5895ad53-48f5-41ef-910c-3615ef5e15e6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_04647a3b-3fec-43c5-b7d8-58c05954539b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_6001d63c-11b3-41ac-8e63-60fb08fad44d" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_04647a3b-3fec-43c5-b7d8-58c05954539b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_c597f9ae-43f3-408d-bedc-16064a9688fc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_6001d63c-11b3-41ac-8e63-60fb08fad44d" xlink:to="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_c597f9ae-43f3-408d-bedc-16064a9688fc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_e99d1ff4-5ee4-473c-a8a0-6e62c18f118b" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_c597f9ae-43f3-408d-bedc-16064a9688fc" xlink:to="loc_srt_RangeAxis_e99d1ff4-5ee4-473c-a8a0-6e62c18f118b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_e99d1ff4-5ee4-473c-a8a0-6e62c18f118b_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_e99d1ff4-5ee4-473c-a8a0-6e62c18f118b" xlink:to="loc_srt_RangeMember_e99d1ff4-5ee4-473c-a8a0-6e62c18f118b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_8d53c040-05dd-4b3e-aca6-258faae5e321" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_e99d1ff4-5ee4-473c-a8a0-6e62c18f118b" xlink:to="loc_srt_RangeMember_8d53c040-05dd-4b3e-aca6-258faae5e321" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_7df731dc-7aa0-443d-a7b3-4b7e933081a7" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_8d53c040-05dd-4b3e-aca6-258faae5e321" xlink:to="loc_srt_MinimumMember_7df731dc-7aa0-443d-a7b3-4b7e933081a7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_7b80dcd7-e9a3-45b3-b3a5-f5f4e7bfe5e2" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_8d53c040-05dd-4b3e-aca6-258faae5e321" xlink:to="loc_srt_MaximumMember_7b80dcd7-e9a3-45b3-b3a5-f5f4e7bfe5e2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_3ff20c82-651b-4fa5-8579-0f473b85dc08" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_c597f9ae-43f3-408d-bedc-16064a9688fc" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_3ff20c82-651b-4fa5-8579-0f473b85dc08" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_3ff20c82-651b-4fa5-8579-0f473b85dc08_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_3ff20c82-651b-4fa5-8579-0f473b85dc08" xlink:to="loc_us-gaap_TypeOfAdoptionMember_3ff20c82-651b-4fa5-8579-0f473b85dc08_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_9a1fa110-23d6-497b-8b1f-b6cff20a3b11" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_3ff20c82-651b-4fa5-8579-0f473b85dc08" xlink:to="loc_us-gaap_TypeOfAdoptionMember_9a1fa110-23d6-497b-8b1f-b6cff20a3b11" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingStandardsUpdate201602Member_009b2164-5bc4-45e2-b3c7-140091a7f5d1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountingStandardsUpdate201602Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_9a1fa110-23d6-497b-8b1f-b6cff20a3b11" xlink:to="loc_us-gaap_AccountingStandardsUpdate201602Member_009b2164-5bc4-45e2-b3c7-140091a7f5d1" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/Acquisitions" xlink:type="simple" xlink:href="amgn-20201231.xsd#Acquisitions"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/Acquisitions" xlink:type="extended" id="i179bbc78cb854e149627ce785f4b9962_Acquisitions"/>
  <link:roleRef roleURI="http://www.amgen.com/role/AcquisitionsTables" xlink:type="simple" xlink:href="amgn-20201231.xsd#AcquisitionsTables"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/AcquisitionsTables" xlink:type="extended" id="i2f373b807798428484ea1c8c4216c43b_AcquisitionsTables"/>
  <link:roleRef roleURI="http://www.amgen.com/role/AcquisitionsNarrativeDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#AcquisitionsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/AcquisitionsNarrativeDetails" xlink:type="extended" id="id42349b62efc4714a7a749ed91412b03_AcquisitionsNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ApprovedMarkets_b71ff025-29bb-4c55-a9de-04c15e81101b" xlink:href="amgn-20201231.xsd#amgn_ApprovedMarkets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:to="loc_amgn_ApprovedMarkets_b71ff025-29bb-4c55-a9de-04c15e81101b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_05de375d-ea2a-4f76-a37a-d8c425370e49" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:to="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_05de375d-ea2a-4f76-a37a-d8c425370e49" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_AcquiredFinitelivedAssetsWeightedAverageUsefulLife_cde3ccf6-2ad2-4f49-8f3a-5d735d7c4949" xlink:href="amgn-20201231.xsd#amgn_AcquiredFinitelivedAssetsWeightedAverageUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:to="loc_amgn_AcquiredFinitelivedAssetsWeightedAverageUsefulLife_cde3ccf6-2ad2-4f49-8f3a-5d735d7c4949" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_819088ee-f536-46c1-8cca-caa526a39132" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_819088ee-f536-46c1-8cca-caa526a39132" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_ac69f1f5-2f2d-4536-896d-e917370f7031" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinitelivedIntangibleAssetsAcquired1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:to="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_ac69f1f5-2f2d-4536-896d-e917370f7031" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_9323c861-75db-4c0c-83ce-b4a4ddeff5a2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:to="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_9323c861-75db-4c0c-83ce-b4a4ddeff5a2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_a80fd174-15b1-4168-97b9-990a1cdf1697" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_a80fd174-15b1-4168-97b9-990a1cdf1697" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireePercentage_2a52a68b-4703-4db9-8dad-28892999cdc2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:to="loc_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireePercentage_2a52a68b-4703-4db9-8dad-28892999cdc2" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeRemeasurementGainOrLoss_82e748bc-4b2a-44d3-9f69-3af291d65cf6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeRemeasurementGainOrLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:to="loc_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeRemeasurementGainOrLoss_82e748bc-4b2a-44d3-9f69-3af291d65cf6" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesGross_24431ee9-35cf-4372-b7f0-04a84dc7ef47" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesGross_24431ee9-35cf-4372-b7f0-04a84dc7ef47" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_BusinessCombinationFairValueofContingentConsiderationArrangementsAdditionfromAcquisitions_7738d7cf-aa9f-4684-bbac-e5d16dd50a3d" xlink:href="amgn-20201231.xsd#amgn_BusinessCombinationFairValueofContingentConsiderationArrangementsAdditionfromAcquisitions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:to="loc_amgn_BusinessCombinationFairValueofContingentConsiderationArrangementsAdditionfromAcquisitions_7738d7cf-aa9f-4684-bbac-e5d16dd50a3d" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_b4132395-0d4b-4a3e-a74b-f3a1e233b2a2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_b4132395-0d4b-4a3e-a74b-f3a1e233b2a2" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_a09539ea-c558-49a8-bcab-9c343870ab06" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_a09539ea-c558-49a8-bcab-9c343870ab06" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities_5eeba287-354f-4a55-acf2-59ac8fb616b5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities_5eeba287-354f-4a55-acf2-59ac8fb616b5" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedOtherAssetsLiabilities_11efac7a-3f5b-4f8a-9a08-7ba95b186603" xlink:href="amgn-20201231.xsd#amgn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedOtherAssetsLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:to="loc_amgn_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedOtherAssetsLiabilities_11efac7a-3f5b-4f8a-9a08-7ba95b186603" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_8002f569-376a-488a-870d-ad62b7820fd4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:to="loc_us-gaap_Goodwill_8002f569-376a-488a-870d-ad62b7820fd4" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentIntangibles_2c9c6f7b-b1a8-43e9-b87f-d78357ae19fa" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentIntangibles"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:to="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentIntangibles_2c9c6f7b-b1a8-43e9-b87f-d78357ae19fa" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentDeferredTaxLiabilities_3da764de-091f-4035-b3da-210a6134073e" xlink:href="amgn-20201231.xsd#amgn_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentDeferredTaxLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:to="loc_amgn_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentDeferredTaxLiabilities_3da764de-091f-4035-b3da-210a6134073e" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentDeferredCredits_e34234e7-00ae-45fa-aa37-d6166c55bb44" xlink:href="amgn-20201231.xsd#amgn_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentDeferredCredits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:to="loc_amgn_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentDeferredCredits_e34234e7-00ae-45fa-aa37-d6166c55bb44" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_EffectiveIncomeTaxRateReconciliationEstimatedBlendedStatutoryRate_b9547234-0f3a-4ef7-8c77-528122511324" xlink:href="amgn-20201231.xsd#amgn_EffectiveIncomeTaxRateReconciliationEstimatedBlendedStatutoryRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:to="loc_amgn_EffectiveIncomeTaxRateReconciliationEstimatedBlendedStatutoryRate_b9547234-0f3a-4ef7-8c77-528122511324" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_37a9e826-f05d-456e-a06c-1be76a648c8e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_147eedb1-0622-4cbd-9a4b-6e7d0507280f" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_37a9e826-f05d-456e-a06c-1be76a648c8e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_AssetsByDescriptionAxis_9ac1531b-5494-4268-8a3d-ef0fab11d266" xlink:href="amgn-20201231.xsd#amgn_AssetsByDescriptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_37a9e826-f05d-456e-a06c-1be76a648c8e" xlink:to="loc_amgn_AssetsByDescriptionAxis_9ac1531b-5494-4268-8a3d-ef0fab11d266" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_AssetsByDescriptionDomain_9ac1531b-5494-4268-8a3d-ef0fab11d266_default" xlink:href="amgn-20201231.xsd#amgn_AssetsByDescriptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_amgn_AssetsByDescriptionAxis_9ac1531b-5494-4268-8a3d-ef0fab11d266" xlink:to="loc_amgn_AssetsByDescriptionDomain_9ac1531b-5494-4268-8a3d-ef0fab11d266_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_AssetsByDescriptionDomain_df741244-ca3c-4084-bdd9-9f937337f816" xlink:href="amgn-20201231.xsd#amgn_AssetsByDescriptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_amgn_AssetsByDescriptionAxis_9ac1531b-5494-4268-8a3d-ef0fab11d266" xlink:to="loc_amgn_AssetsByDescriptionDomain_df741244-ca3c-4084-bdd9-9f937337f816" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_AssembledWorkforceMember_d6110ec2-ae65-4b6d-8067-6439fdd68497" xlink:href="amgn-20201231.xsd#amgn_AssembledWorkforceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amgn_AssetsByDescriptionDomain_df741244-ca3c-4084-bdd9-9f937337f816" xlink:to="loc_amgn_AssembledWorkforceMember_d6110ec2-ae65-4b6d-8067-6439fdd68497" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoriesMember_7cfd05fa-b0d2-4e97-87f4-21994bfffc53" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InventoriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amgn_AssetsByDescriptionDomain_df741244-ca3c-4084-bdd9-9f937337f816" xlink:to="loc_us-gaap_InventoriesMember_7cfd05fa-b0d2-4e97-87f4-21994bfffc53" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_22db6ddb-7ccb-4986-ae9f-05e7095ca360" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_37a9e826-f05d-456e-a06c-1be76a648c8e" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_22db6ddb-7ccb-4986-ae9f-05e7095ca360" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_22db6ddb-7ccb-4986-ae9f-05e7095ca360_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_22db6ddb-7ccb-4986-ae9f-05e7095ca360" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_22db6ddb-7ccb-4986-ae9f-05e7095ca360_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_f1b57cab-41f7-4558-a294-cf8aee7e046a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_22db6ddb-7ccb-4986-ae9f-05e7095ca360" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_f1b57cab-41f7-4558-a294-cf8aee7e046a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_OtezlaMember_88fa7d04-97ae-4907-a1a6-b724de785f82" xlink:href="amgn-20201231.xsd#amgn_OtezlaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_f1b57cab-41f7-4558-a294-cf8aee7e046a" xlink:to="loc_amgn_OtezlaMember_88fa7d04-97ae-4907-a1a6-b724de785f82" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_NuevolutionMember_ccac54d1-414c-4cf8-a823-118c58171680" xlink:href="amgn-20201231.xsd#amgn_NuevolutionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_f1b57cab-41f7-4558-a294-cf8aee7e046a" xlink:to="loc_amgn_NuevolutionMember_ccac54d1-414c-4cf8-a823-118c58171680" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_KirinAmgenInc.KAMember_4aac8d17-5e15-4b7c-92ed-9159f62b27ad" xlink:href="amgn-20201231.xsd#amgn_KirinAmgenInc.KAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_f1b57cab-41f7-4558-a294-cf8aee7e046a" xlink:to="loc_amgn_KirinAmgenInc.KAMember_4aac8d17-5e15-4b7c-92ed-9159f62b27ad" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_0da5c341-1aed-4c60-bc36-5d3a331e6bf4" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_37a9e826-f05d-456e-a06c-1be76a648c8e" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_0da5c341-1aed-4c60-bc36-5d3a331e6bf4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_0da5c341-1aed-4c60-bc36-5d3a331e6bf4_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_0da5c341-1aed-4c60-bc36-5d3a331e6bf4" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_0da5c341-1aed-4c60-bc36-5d3a331e6bf4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_6019ea28-70c6-404f-88dd-d331dda9af49" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_0da5c341-1aed-4c60-bc36-5d3a331e6bf4" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_6019ea28-70c6-404f-88dd-d331dda9af49" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_KirinAmgenInc.KAMember_f7cc8cfa-3a37-4062-9345-7f92384e2314" xlink:href="amgn-20201231.xsd#amgn_KirinAmgenInc.KAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_6019ea28-70c6-404f-88dd-d331dda9af49" xlink:to="loc_amgn_KirinAmgenInc.KAMember_f7cc8cfa-3a37-4062-9345-7f92384e2314" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_dcd1f993-ff6f-4896-a9dd-106b4f476665" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_37a9e826-f05d-456e-a06c-1be76a648c8e" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_dcd1f993-ff6f-4896-a9dd-106b4f476665" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_dcd1f993-ff6f-4896-a9dd-106b4f476665_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_dcd1f993-ff6f-4896-a9dd-106b4f476665" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_dcd1f993-ff6f-4896-a9dd-106b4f476665_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_cec918a0-b0d0-40ad-9a4e-0e93e8ea9f05" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_dcd1f993-ff6f-4896-a9dd-106b4f476665" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_cec918a0-b0d0-40ad-9a4e-0e93e8ea9f05" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DevelopedTechnologyRightsMember_62763784-2df4-42ef-a4e7-c5f2fcd870e4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DevelopedTechnologyRightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_cec918a0-b0d0-40ad-9a4e-0e93e8ea9f05" xlink:to="loc_us-gaap_DevelopedTechnologyRightsMember_62763784-2df4-42ef-a4e7-c5f2fcd870e4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_MarketingRelatedRightsMember_b86a05d5-9325-4f4c-84df-f3d285d60be3" xlink:href="amgn-20201231.xsd#amgn_MarketingRelatedRightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_cec918a0-b0d0-40ad-9a4e-0e93e8ea9f05" xlink:to="loc_amgn_MarketingRelatedRightsMember_b86a05d5-9325-4f4c-84df-f3d285d60be3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_RDTechnologyrightsMember_2fbec864-43be-440c-8719-49d8949f2295" xlink:href="amgn-20201231.xsd#amgn_RDTechnologyrightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_cec918a0-b0d0-40ad-9a4e-0e93e8ea9f05" xlink:to="loc_amgn_RDTechnologyrightsMember_2fbec864-43be-440c-8719-49d8949f2295" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LicensingAgreementsMember_5bb61160-f374-4fc0-89ce-2d36ceb10e99" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LicensingAgreementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_cec918a0-b0d0-40ad-9a4e-0e93e8ea9f05" xlink:to="loc_us-gaap_LicensingAgreementsMember_5bb61160-f374-4fc0-89ce-2d36ceb10e99" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/AcquisitionsOtezlaDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#AcquisitionsOtezlaDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/AcquisitionsOtezlaDetails" xlink:type="extended" id="i38c6ff2693e74d60b0a88c18e2c2101c_AcquisitionsOtezlaDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_197f7c8b-353a-49a1-88d6-da1dfe738384" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract_d56e3461-929e-449c-bb8d-ba4fecaba209" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_197f7c8b-353a-49a1-88d6-da1dfe738384" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract_d56e3461-929e-449c-bb8d-ba4fecaba209" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesGross_6d012ae7-facf-4f24-8ac5-5ffc321871a1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract_d56e3461-929e-449c-bb8d-ba4fecaba209" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesGross_6d012ae7-facf-4f24-8ac5-5ffc321871a1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_Transactioncostsassetacquisition_54edf5a7-af25-415a-861d-d94b3bd14859" xlink:href="amgn-20201231.xsd#amgn_Transactioncostsassetacquisition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract_d56e3461-929e-449c-bb8d-ba4fecaba209" xlink:to="loc_amgn_Transactioncostsassetacquisition_54edf5a7-af25-415a-861d-d94b3bd14859" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_Businessassetacquisitionconsiderationtransferred_460930ed-3e1d-4a08-999d-2b60350b57ff" xlink:href="amgn-20201231.xsd#amgn_Businessassetacquisitionconsiderationtransferred"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract_d56e3461-929e-449c-bb8d-ba4fecaba209" xlink:to="loc_amgn_Businessassetacquisitionconsiderationtransferred_460930ed-3e1d-4a08-999d-2b60350b57ff" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwillAbstract_55c34802-76f9-4b1d-9c93-f29690c3923d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwillAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract_d56e3461-929e-449c-bb8d-ba4fecaba209" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwillAbstract_55c34802-76f9-4b1d-9c93-f29690c3923d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_BusinessacquiredassetacquisitionFinitelivedintangibleassetsacquired_8bbccf44-a115-4a50-9c0c-89bf03f8efe6" xlink:href="amgn-20201231.xsd#amgn_BusinessacquiredassetacquisitionFinitelivedintangibleassetsacquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwillAbstract_55c34802-76f9-4b1d-9c93-f29690c3923d" xlink:to="loc_amgn_BusinessacquiredassetacquisitionFinitelivedintangibleassetsacquired_8bbccf44-a115-4a50-9c0c-89bf03f8efe6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_BusinessacquiredassetacquisitionInventoryacquired_ee082c5a-b74a-43c9-bb42-a89f8ffb0dbb" xlink:href="amgn-20201231.xsd#amgn_BusinessacquiredassetacquisitionInventoryacquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract_d56e3461-929e-449c-bb8d-ba4fecaba209" xlink:to="loc_amgn_BusinessacquiredassetacquisitionInventoryacquired_ee082c5a-b74a-43c9-bb42-a89f8ffb0dbb" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_BusinessacquiredassetacquisitionDeferredTaxLiabilities_764cb0c9-dc94-4bee-af26-237bbe265898" xlink:href="amgn-20201231.xsd#amgn_BusinessacquiredassetacquisitionDeferredTaxLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract_d56e3461-929e-449c-bb8d-ba4fecaba209" xlink:to="loc_amgn_BusinessacquiredassetacquisitionDeferredTaxLiabilities_764cb0c9-dc94-4bee-af26-237bbe265898" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_BusinessacquiredassetacquisitionDeferredCredit_fa48b97d-0a1c-449b-a087-1f5cb1c27bdb" xlink:href="amgn-20201231.xsd#amgn_BusinessacquiredassetacquisitionDeferredCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract_d56e3461-929e-449c-bb8d-ba4fecaba209" xlink:to="loc_amgn_BusinessacquiredassetacquisitionDeferredCredit_fa48b97d-0a1c-449b-a087-1f5cb1c27bdb" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_BusinessacquiredassetacquisitionNoncurrentLiabilitiesOther_00217fc4-f23a-452d-8660-f6820db6971a" xlink:href="amgn-20201231.xsd#amgn_BusinessacquiredassetacquisitionNoncurrentLiabilitiesOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract_d56e3461-929e-449c-bb8d-ba4fecaba209" xlink:to="loc_amgn_BusinessacquiredassetacquisitionNoncurrentLiabilitiesOther_00217fc4-f23a-452d-8660-f6820db6971a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_BusinessacquiredassetacquisitionAssetsacquiredandLiabilitiesassumednet_dea9e596-c22e-4488-a6d8-f65fff423244" xlink:href="amgn-20201231.xsd#amgn_BusinessacquiredassetacquisitionAssetsacquiredandLiabilitiesassumednet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract_d56e3461-929e-449c-bb8d-ba4fecaba209" xlink:to="loc_amgn_BusinessacquiredassetacquisitionAssetsacquiredandLiabilitiesassumednet_dea9e596-c22e-4488-a6d8-f65fff423244" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_993db19c-f52c-4786-9959-a15ffca62a3d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_197f7c8b-353a-49a1-88d6-da1dfe738384" xlink:to="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_993db19c-f52c-4786-9959-a15ffca62a3d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e9af94f3-9096-4687-ad11-1928ed3ebfba" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_197f7c8b-353a-49a1-88d6-da1dfe738384" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e9af94f3-9096-4687-ad11-1928ed3ebfba" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_10aec0a3-4e6d-4caf-b0ce-64d5e5ded95b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e9af94f3-9096-4687-ad11-1928ed3ebfba" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_10aec0a3-4e6d-4caf-b0ce-64d5e5ded95b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_10aec0a3-4e6d-4caf-b0ce-64d5e5ded95b_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_10aec0a3-4e6d-4caf-b0ce-64d5e5ded95b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_10aec0a3-4e6d-4caf-b0ce-64d5e5ded95b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_651e12db-fc68-4112-b49f-4a190ac97375" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_10aec0a3-4e6d-4caf-b0ce-64d5e5ded95b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_651e12db-fc68-4112-b49f-4a190ac97375" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DevelopedTechnologyRightsMember_dd8848fd-dc75-4f43-8c90-54551ee3c4e0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DevelopedTechnologyRightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_651e12db-fc68-4112-b49f-4a190ac97375" xlink:to="loc_us-gaap_DevelopedTechnologyRightsMember_dd8848fd-dc75-4f43-8c90-54551ee3c4e0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_MarketingRelatedRightsMember_3b88b77a-d38a-4dbc-b3f3-8a07f35f6167" xlink:href="amgn-20201231.xsd#amgn_MarketingRelatedRightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_651e12db-fc68-4112-b49f-4a190ac97375" xlink:to="loc_amgn_MarketingRelatedRightsMember_3b88b77a-d38a-4dbc-b3f3-8a07f35f6167" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_b3525730-b8eb-4cbc-abb0-64faef1d340f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e9af94f3-9096-4687-ad11-1928ed3ebfba" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_b3525730-b8eb-4cbc-abb0-64faef1d340f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_b3525730-b8eb-4cbc-abb0-64faef1d340f_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_b3525730-b8eb-4cbc-abb0-64faef1d340f" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_b3525730-b8eb-4cbc-abb0-64faef1d340f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_104415e5-1933-4d0c-b615-be4836c9d4fb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_b3525730-b8eb-4cbc-abb0-64faef1d340f" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_104415e5-1933-4d0c-b615-be4836c9d4fb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_OtezlaMember_5b65c153-3847-4b2c-937b-d4f5378ac940" xlink:href="amgn-20201231.xsd#amgn_OtezlaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_104415e5-1933-4d0c-b615-be4836c9d4fb" xlink:to="loc_amgn_OtezlaMember_5b65c153-3847-4b2c-937b-d4f5378ac940" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_AssetsByDescriptionAxis_f0828877-d987-47e9-86ab-32fd2cc3f9c3" xlink:href="amgn-20201231.xsd#amgn_AssetsByDescriptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e9af94f3-9096-4687-ad11-1928ed3ebfba" xlink:to="loc_amgn_AssetsByDescriptionAxis_f0828877-d987-47e9-86ab-32fd2cc3f9c3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_AssetsByDescriptionDomain_f0828877-d987-47e9-86ab-32fd2cc3f9c3_default" xlink:href="amgn-20201231.xsd#amgn_AssetsByDescriptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_amgn_AssetsByDescriptionAxis_f0828877-d987-47e9-86ab-32fd2cc3f9c3" xlink:to="loc_amgn_AssetsByDescriptionDomain_f0828877-d987-47e9-86ab-32fd2cc3f9c3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_AssetsByDescriptionDomain_50bd6e2e-81eb-4631-bc2e-bdc599e468bd" xlink:href="amgn-20201231.xsd#amgn_AssetsByDescriptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_amgn_AssetsByDescriptionAxis_f0828877-d987-47e9-86ab-32fd2cc3f9c3" xlink:to="loc_amgn_AssetsByDescriptionDomain_50bd6e2e-81eb-4631-bc2e-bdc599e468bd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_AssembledWorkforceMember_aec988de-741f-48e4-b7c2-bd7d33fd45fb" xlink:href="amgn-20201231.xsd#amgn_AssembledWorkforceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amgn_AssetsByDescriptionDomain_50bd6e2e-81eb-4631-bc2e-bdc599e468bd" xlink:to="loc_amgn_AssembledWorkforceMember_aec988de-741f-48e4-b7c2-bd7d33fd45fb" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/AcquisitionsAggregateConsiderationPaidDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#AcquisitionsAggregateConsiderationPaidDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/AcquisitionsAggregateConsiderationPaidDetails" xlink:type="extended" id="i0af9d5e5aab142c58eeb982b44269908_AcquisitionsAggregateConsiderationPaidDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_9e3fa8e9-e833-47a6-a2c0-69ef28bbff75" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_c67ab3cb-35c9-4ec4-99e6-b51593141ee1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9e3fa8e9-e833-47a6-a2c0-69ef28bbff75" xlink:to="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_c67ab3cb-35c9-4ec4-99e6-b51593141ee1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesGross_4bea891e-7cc2-48e8-bdd4-d1edf92ae33a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9e3fa8e9-e833-47a6-a2c0-69ef28bbff75" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesGross_4bea891e-7cc2-48e8-bdd4-d1edf92ae33a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_BusinessCombinationFairValueofContingentConsiderationArrangementsAdditionfromAcquisitions_52a05792-ebd7-4ed4-80fd-1a24b3e74b0c" xlink:href="amgn-20201231.xsd#amgn_BusinessCombinationFairValueofContingentConsiderationArrangementsAdditionfromAcquisitions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9e3fa8e9-e833-47a6-a2c0-69ef28bbff75" xlink:to="loc_amgn_BusinessCombinationFairValueofContingentConsiderationArrangementsAdditionfromAcquisitions_52a05792-ebd7-4ed4-80fd-1a24b3e74b0c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeRemeasurementLoss_13d76e1e-747e-43dc-bbc5-92c5d72a208d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeRemeasurementLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9e3fa8e9-e833-47a6-a2c0-69ef28bbff75" xlink:to="loc_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeRemeasurementLoss_13d76e1e-747e-43dc-bbc5-92c5d72a208d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_9ac58e78-d16f-4247-b9b4-91b4d6785905" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9e3fa8e9-e833-47a6-a2c0-69ef28bbff75" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_9ac58e78-d16f-4247-b9b4-91b4d6785905" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeFairValue1_2d2e3ac8-0bb6-476f-b5ac-bd334187c346" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeFairValue1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9e3fa8e9-e833-47a6-a2c0-69ef28bbff75" xlink:to="loc_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeFairValue1_2d2e3ac8-0bb6-476f-b5ac-bd334187c346" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferredIncludingEquityInterestInAcquireeHeldPriorToCombination1_ea1691ee-a9d2-4587-b6e1-5908a3f3c793" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferredIncludingEquityInterestInAcquireeHeldPriorToCombination1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9e3fa8e9-e833-47a6-a2c0-69ef28bbff75" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferredIncludingEquityInterestInAcquireeHeldPriorToCombination1_ea1691ee-a9d2-4587-b6e1-5908a3f3c793" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_a479c6a5-cc65-422f-9ec7-4a9b4e4cf2bc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9e3fa8e9-e833-47a6-a2c0-69ef28bbff75" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_a479c6a5-cc65-422f-9ec7-4a9b4e4cf2bc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_eb056059-28b8-4e3e-a18a-049193e5f65d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_a479c6a5-cc65-422f-9ec7-4a9b4e4cf2bc" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_eb056059-28b8-4e3e-a18a-049193e5f65d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_eb056059-28b8-4e3e-a18a-049193e5f65d_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_eb056059-28b8-4e3e-a18a-049193e5f65d" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_eb056059-28b8-4e3e-a18a-049193e5f65d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_1edb71c7-e18e-4d4f-bc52-f00f0436e976" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_eb056059-28b8-4e3e-a18a-049193e5f65d" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_1edb71c7-e18e-4d4f-bc52-f00f0436e976" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_RDTechnologyrightsMember_06a920b8-f431-4b78-91a4-590ff52c76dd" xlink:href="amgn-20201231.xsd#amgn_RDTechnologyrightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_1edb71c7-e18e-4d4f-bc52-f00f0436e976" xlink:to="loc_amgn_RDTechnologyrightsMember_06a920b8-f431-4b78-91a4-590ff52c76dd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_031e2392-5f94-4693-b70c-7712d3a8ac34" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_a479c6a5-cc65-422f-9ec7-4a9b4e4cf2bc" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_031e2392-5f94-4693-b70c-7712d3a8ac34" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_031e2392-5f94-4693-b70c-7712d3a8ac34_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_031e2392-5f94-4693-b70c-7712d3a8ac34" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_031e2392-5f94-4693-b70c-7712d3a8ac34_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_30cf99e2-368e-4076-9e0b-675360e975f2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_031e2392-5f94-4693-b70c-7712d3a8ac34" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_30cf99e2-368e-4076-9e0b-675360e975f2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_NuevolutionMember_99283526-f2ea-4175-ac36-59c1d236225e" xlink:href="amgn-20201231.xsd#amgn_NuevolutionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_30cf99e2-368e-4076-9e0b-675360e975f2" xlink:to="loc_amgn_NuevolutionMember_99283526-f2ea-4175-ac36-59c1d236225e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_KirinAmgenInc.KAMember_eef8743b-ca25-47d9-994a-a47d285092b9" xlink:href="amgn-20201231.xsd#amgn_KirinAmgenInc.KAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_30cf99e2-368e-4076-9e0b-675360e975f2" xlink:to="loc_amgn_KirinAmgenInc.KAMember_eef8743b-ca25-47d9-994a-a47d285092b9" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/Revenues" xlink:type="simple" xlink:href="amgn-20201231.xsd#Revenues"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/Revenues" xlink:type="extended" id="i85183f9eadf941319752af9609ee6eda_Revenues"/>
  <link:roleRef roleURI="http://www.amgen.com/role/RevenuesTables" xlink:type="simple" xlink:href="amgn-20201231.xsd#RevenuesTables"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/RevenuesTables" xlink:type="extended" id="iaf5a72ce178f42308d93882354a83a09_RevenuesTables"/>
  <link:roleRef roleURI="http://www.amgen.com/role/RevenuesNarrativeDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#RevenuesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/RevenuesNarrativeDetails" xlink:type="extended" id="i7d43ed1784bd4cd98d76e40dfbada9ba_RevenuesNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_504bab93-576a-4dd6-b659-674aa5388921" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_NumberOfCustomersAccountingForMoreThanTenPercentOfRevenue_f1366e1f-9e6b-4ed8-be30-a91681985ba6" xlink:href="amgn-20201231.xsd#amgn_NumberOfCustomersAccountingForMoreThanTenPercentOfRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_504bab93-576a-4dd6-b659-674aa5388921" xlink:to="loc_amgn_NumberOfCustomersAccountingForMoreThanTenPercentOfRevenue_f1366e1f-9e6b-4ed8-be30-a91681985ba6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_NumberOfCustomersAccountingForMoreThanTenPercentOfGrossTradeReceivables_7cb3d92a-2755-45c8-a4cd-0451ca96f6b8" xlink:href="amgn-20201231.xsd#amgn_NumberOfCustomersAccountingForMoreThanTenPercentOfGrossTradeReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_504bab93-576a-4dd6-b659-674aa5388921" xlink:to="loc_amgn_NumberOfCustomersAccountingForMoreThanTenPercentOfGrossTradeReceivables_7cb3d92a-2755-45c8-a4cd-0451ca96f6b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_PercentageOfCombinedNetTradeReceivablesFromMajorCustomers_92a696af-66c0-4668-9c39-4bedda40b51f" xlink:href="amgn-20201231.xsd#amgn_PercentageOfCombinedNetTradeReceivablesFromMajorCustomers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_504bab93-576a-4dd6-b659-674aa5388921" xlink:to="loc_amgn_PercentageOfCombinedNetTradeReceivablesFromMajorCustomers_92a696af-66c0-4668-9c39-4bedda40b51f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_PercentageOfCombinedWorldwideGrossRevenuesFromMajorCustomers_fc5b3e6a-9d56-47a0-bf9d-fb8ce1d7140b" xlink:href="amgn-20201231.xsd#amgn_PercentageOfCombinedWorldwideGrossRevenuesFromMajorCustomers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_504bab93-576a-4dd6-b659-674aa5388921" xlink:to="loc_amgn_PercentageOfCombinedWorldwideGrossRevenuesFromMajorCustomers_fc5b3e6a-9d56-47a0-bf9d-fb8ce1d7140b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_cd8523b9-4700-4e72-8ab7-fc6352d8f1f5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_504bab93-576a-4dd6-b659-674aa5388921" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_cd8523b9-4700-4e72-8ab7-fc6352d8f1f5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_PercentageOfNetAmountDueFromCustomersLocatedOutsideDomesticLocation_0b467fce-7dc6-4075-a5db-f7ea282fd0d5" xlink:href="amgn-20201231.xsd#amgn_PercentageOfNetAmountDueFromCustomersLocatedOutsideDomesticLocation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_504bab93-576a-4dd6-b659-674aa5388921" xlink:to="loc_amgn_PercentageOfNetAmountDueFromCustomersLocatedOutsideDomesticLocation_0b467fce-7dc6-4075-a5db-f7ea282fd0d5" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_1ca5d41f-2c8c-422c-8f17-84db343548df" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_504bab93-576a-4dd6-b659-674aa5388921" xlink:to="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_1ca5d41f-2c8c-422c-8f17-84db343548df" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_e7ca0748-f91f-41f1-8cb5-cee7271d760d" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_1ca5d41f-2c8c-422c-8f17-84db343548df" xlink:to="loc_srt_MajorCustomersAxis_e7ca0748-f91f-41f1-8cb5-cee7271d760d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_e7ca0748-f91f-41f1-8cb5-cee7271d760d_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_e7ca0748-f91f-41f1-8cb5-cee7271d760d" xlink:to="loc_srt_NameOfMajorCustomerDomain_e7ca0748-f91f-41f1-8cb5-cee7271d760d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_11ba2635-8de1-49bd-a558-03a513ccf547" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_e7ca0748-f91f-41f1-8cb5-cee7271d760d" xlink:to="loc_srt_NameOfMajorCustomerDomain_11ba2635-8de1-49bd-a558-03a513ccf547" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CustomerOneMember_66fbfa2a-5fcd-4ce3-97c9-7acffc0b9051" xlink:href="amgn-20201231.xsd#amgn_CustomerOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_11ba2635-8de1-49bd-a558-03a513ccf547" xlink:to="loc_amgn_CustomerOneMember_66fbfa2a-5fcd-4ce3-97c9-7acffc0b9051" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CustomerTwoMember_d07896d2-6e11-4053-9f91-4c6dd55bc2fb" xlink:href="amgn-20201231.xsd#amgn_CustomerTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_11ba2635-8de1-49bd-a558-03a513ccf547" xlink:to="loc_amgn_CustomerTwoMember_d07896d2-6e11-4053-9f91-4c6dd55bc2fb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CustomerThreeMember_1d53f557-8dcb-445e-9d62-13191dc1f26b" xlink:href="amgn-20201231.xsd#amgn_CustomerThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_11ba2635-8de1-49bd-a558-03a513ccf547" xlink:to="loc_amgn_CustomerThreeMember_1d53f557-8dcb-445e-9d62-13191dc1f26b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_63263355-3551-4227-a5d1-34d1e136fd64" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_1ca5d41f-2c8c-422c-8f17-84db343548df" xlink:to="loc_srt_ProductOrServiceAxis_63263355-3551-4227-a5d1-34d1e136fd64" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_63263355-3551-4227-a5d1-34d1e136fd64_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_63263355-3551-4227-a5d1-34d1e136fd64" xlink:to="loc_srt_ProductsAndServicesDomain_63263355-3551-4227-a5d1-34d1e136fd64_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_188633ae-9c96-4141-bb10-ad0c693782e7" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_63263355-3551-4227-a5d1-34d1e136fd64" xlink:to="loc_srt_ProductsAndServicesDomain_188633ae-9c96-4141-bb10-ad0c693782e7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductMember_57f05dbb-55b9-41f0-9b90-22ed45a8a545" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_188633ae-9c96-4141-bb10-ad0c693782e7" xlink:to="loc_us-gaap_ProductMember_57f05dbb-55b9-41f0-9b90-22ed45a8a545" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_EnbrelMember_6c6d311a-87b0-4019-a229-e410ec99f257" xlink:href="amgn-20201231.xsd#amgn_EnbrelMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductMember_57f05dbb-55b9-41f0-9b90-22ed45a8a545" xlink:to="loc_amgn_EnbrelMember_6c6d311a-87b0-4019-a229-e410ec99f257" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ProliaMember_9303a672-3059-46fe-bb08-86c2930b0bce" xlink:href="amgn-20201231.xsd#amgn_ProliaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductMember_57f05dbb-55b9-41f0-9b90-22ed45a8a545" xlink:to="loc_amgn_ProliaMember_9303a672-3059-46fe-bb08-86c2930b0bce" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_NeulastaMember_b2746457-03c6-4803-8369-b7c25677ffeb" xlink:href="amgn-20201231.xsd#amgn_NeulastaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductMember_57f05dbb-55b9-41f0-9b90-22ed45a8a545" xlink:to="loc_amgn_NeulastaMember_b2746457-03c6-4803-8369-b7c25677ffeb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_OtezlaMember_57c1e4b1-ef0e-475c-b1b7-e0919fb6202f" xlink:href="amgn-20201231.xsd#amgn_OtezlaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductMember_57f05dbb-55b9-41f0-9b90-22ed45a8a545" xlink:to="loc_amgn_OtezlaMember_57c1e4b1-ef0e-475c-b1b7-e0919fb6202f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_XgevaMember_7dd87efa-5827-4a5e-9c24-5cf238b4c332" xlink:href="amgn-20201231.xsd#amgn_XgevaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductMember_57f05dbb-55b9-41f0-9b90-22ed45a8a545" xlink:to="loc_amgn_XgevaMember_7dd87efa-5827-4a5e-9c24-5cf238b4c332" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_AranespMember_4d5804f2-48ac-462e-81bf-f8a40c9d621f" xlink:href="amgn-20201231.xsd#amgn_AranespMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductMember_57f05dbb-55b9-41f0-9b90-22ed45a8a545" xlink:to="loc_amgn_AranespMember_4d5804f2-48ac-462e-81bf-f8a40c9d621f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_KyprolisMember_fff3a940-8734-4136-b0fa-9bdb4324e6ec" xlink:href="amgn-20201231.xsd#amgn_KyprolisMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductMember_57f05dbb-55b9-41f0-9b90-22ed45a8a545" xlink:to="loc_amgn_KyprolisMember_fff3a940-8734-4136-b0fa-9bdb4324e6ec" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_RepathaevolocumabMember_2b0273d6-9a94-43e4-a4c6-50e7b4fbca4f" xlink:href="amgn-20201231.xsd#amgn_RepathaevolocumabMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductMember_57f05dbb-55b9-41f0-9b90-22ed45a8a545" xlink:to="loc_amgn_RepathaevolocumabMember_2b0273d6-9a94-43e4-a4c6-50e7b4fbca4f" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_OtherProductsMember_7da03712-ab0a-4986-b769-ae20bd4c8772" xlink:href="amgn-20201231.xsd#amgn_OtherProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductMember_57f05dbb-55b9-41f0-9b90-22ed45a8a545" xlink:to="loc_amgn_OtherProductsMember_7da03712-ab0a-4986-b769-ae20bd4c8772" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductAndServiceOtherMember_e0de3948-5f46-4430-be09-1396fc684187" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProductAndServiceOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_188633ae-9c96-4141-bb10-ad0c693782e7" xlink:to="loc_us-gaap_ProductAndServiceOtherMember_e0de3948-5f46-4430-be09-1396fc684187" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_1039bb53-bf75-4737-aee3-1e9f6a089924" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_1ca5d41f-2c8c-422c-8f17-84db343548df" xlink:to="loc_srt_StatementGeographicalAxis_1039bb53-bf75-4737-aee3-1e9f6a089924" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_1039bb53-bf75-4737-aee3-1e9f6a089924_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_1039bb53-bf75-4737-aee3-1e9f6a089924" xlink:to="loc_srt_SegmentGeographicalDomain_1039bb53-bf75-4737-aee3-1e9f6a089924_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_e307744a-2956-408b-a804-a239f51b158b" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_1039bb53-bf75-4737-aee3-1e9f6a089924" xlink:to="loc_srt_SegmentGeographicalDomain_e307744a-2956-408b-a804-a239f51b158b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_6c0cef20-9075-4e7e-92f9-41aee08bec1a" xlink:href="https://xbrl.sec.gov/country/2020/country-2020-01-31.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_e307744a-2956-408b-a804-a239f51b158b" xlink:to="loc_country_US_6c0cef20-9075-4e7e-92f9-41aee08bec1a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonUsMember_f0c86b04-5956-48ac-a64f-6cf2eb057cd9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NonUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_e307744a-2956-408b-a804-a239f51b158b" xlink:to="loc_us-gaap_NonUsMember_f0c86b04-5956-48ac-a64f-6cf2eb057cd9" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/RevenuesCustomerConcentrationProductSalesDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#RevenuesCustomerConcentrationProductSalesDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/RevenuesCustomerConcentrationProductSalesDetails" xlink:type="extended" id="i1517940c799e42d8be3a230c158406cf_RevenuesCustomerConcentrationProductSalesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_b7eaea70-5599-4c3d-a4bc-301caf097222" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EntityWideRevenueMajorCustomerLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_28a65cfe-8a67-4f53-93bc-96f04481115e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_b7eaea70-5599-4c3d-a4bc-301caf097222" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_28a65cfe-8a67-4f53-93bc-96f04481115e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_PercentageOfGrossRevenues_2b997e9d-3fd6-4bba-a1db-16fff6fa45b7" xlink:href="amgn-20201231.xsd#amgn_PercentageOfGrossRevenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_b7eaea70-5599-4c3d-a4bc-301caf097222" xlink:to="loc_amgn_PercentageOfGrossRevenues_2b997e9d-3fd6-4bba-a1db-16fff6fa45b7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_NumberOfCustomersAccountingForMoreThanTenPercentOfRevenue_77afc4ec-4434-4d13-aa59-ad6d7414f40d" xlink:href="amgn-20201231.xsd#amgn_NumberOfCustomersAccountingForMoreThanTenPercentOfRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_b7eaea70-5599-4c3d-a4bc-301caf097222" xlink:to="loc_amgn_NumberOfCustomersAccountingForMoreThanTenPercentOfRevenue_77afc4ec-4434-4d13-aa59-ad6d7414f40d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ThresholdForDisclosureOfProductSalesToMajorCustomers_ca762970-c771-412d-8e1c-db0ab708c809" xlink:href="amgn-20201231.xsd#amgn_ThresholdForDisclosureOfProductSalesToMajorCustomers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_b7eaea70-5599-4c3d-a4bc-301caf097222" xlink:to="loc_amgn_ThresholdForDisclosureOfProductSalesToMajorCustomers_ca762970-c771-412d-8e1c-db0ab708c809" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_NumberOfCustomersAccountingForMoreThanTenPercentOfGrossTradeReceivables_02e4ab7d-eccc-4d0c-8383-034a3247fb11" xlink:href="amgn-20201231.xsd#amgn_NumberOfCustomersAccountingForMoreThanTenPercentOfGrossTradeReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_b7eaea70-5599-4c3d-a4bc-301caf097222" xlink:to="loc_amgn_NumberOfCustomersAccountingForMoreThanTenPercentOfGrossTradeReceivables_02e4ab7d-eccc-4d0c-8383-034a3247fb11" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_ee586c9e-dbd7-482e-b95f-fbb50665ba54" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_b7eaea70-5599-4c3d-a4bc-301caf097222" xlink:to="loc_us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_ee586c9e-dbd7-482e-b95f-fbb50665ba54" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_787b4774-6a38-4606-9687-a66f2562aa36" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_ee586c9e-dbd7-482e-b95f-fbb50665ba54" xlink:to="loc_srt_ProductOrServiceAxis_787b4774-6a38-4606-9687-a66f2562aa36" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_787b4774-6a38-4606-9687-a66f2562aa36_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_787b4774-6a38-4606-9687-a66f2562aa36" xlink:to="loc_srt_ProductsAndServicesDomain_787b4774-6a38-4606-9687-a66f2562aa36_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_52ed99a1-43a5-4484-b913-e164477a42f6" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_787b4774-6a38-4606-9687-a66f2562aa36" xlink:to="loc_srt_ProductsAndServicesDomain_52ed99a1-43a5-4484-b913-e164477a42f6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductMember_384d8a89-3283-406d-9e90-77f2cd00db69" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_52ed99a1-43a5-4484-b913-e164477a42f6" xlink:to="loc_us-gaap_ProductMember_384d8a89-3283-406d-9e90-77f2cd00db69" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_62eadeb6-4dd6-44f3-a14a-fd7d41f2542b" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_ee586c9e-dbd7-482e-b95f-fbb50665ba54" xlink:to="loc_srt_MajorCustomersAxis_62eadeb6-4dd6-44f3-a14a-fd7d41f2542b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_62eadeb6-4dd6-44f3-a14a-fd7d41f2542b_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_62eadeb6-4dd6-44f3-a14a-fd7d41f2542b" xlink:to="loc_srt_NameOfMajorCustomerDomain_62eadeb6-4dd6-44f3-a14a-fd7d41f2542b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_6968b2eb-8836-4937-80d7-73f45e4f3b1e" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_62eadeb6-4dd6-44f3-a14a-fd7d41f2542b" xlink:to="loc_srt_NameOfMajorCustomerDomain_6968b2eb-8836-4937-80d7-73f45e4f3b1e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CustomerOneMember_c07e72a8-5f11-4a66-a015-ca277f22c3fa" xlink:href="amgn-20201231.xsd#amgn_CustomerOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_6968b2eb-8836-4937-80d7-73f45e4f3b1e" xlink:to="loc_amgn_CustomerOneMember_c07e72a8-5f11-4a66-a015-ca277f22c3fa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CustomerTwoMember_2996d45c-effe-4322-8187-603be3f36912" xlink:href="amgn-20201231.xsd#amgn_CustomerTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_6968b2eb-8836-4937-80d7-73f45e4f3b1e" xlink:to="loc_amgn_CustomerTwoMember_2996d45c-effe-4322-8187-603be3f36912" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CustomerThreeMember_59a4af3a-7912-43a1-a6f5-7b930a652d0c" xlink:href="amgn-20201231.xsd#amgn_CustomerThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_6968b2eb-8836-4937-80d7-73f45e4f3b1e" xlink:to="loc_amgn_CustomerThreeMember_59a4af3a-7912-43a1-a6f5-7b930a652d0c" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/Stockbasedcompensation" xlink:type="simple" xlink:href="amgn-20201231.xsd#Stockbasedcompensation"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/Stockbasedcompensation" xlink:type="extended" id="icb84e49dcf3141c5a40dbdf33f546811_Stockbasedcompensation"/>
  <link:roleRef roleURI="http://www.amgen.com/role/StockbasedcompensationTables" xlink:type="simple" xlink:href="amgn-20201231.xsd#StockbasedcompensationTables"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/StockbasedcompensationTables" xlink:type="extended" id="i9093196ec42f4386bef1f0412df26848_StockbasedcompensationTables"/>
  <link:roleRef roleURI="http://www.amgen.com/role/StockbasedcompensationTextualDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#StockbasedcompensationTextualDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/StockbasedcompensationTextualDetails" xlink:type="extended" id="i58f1c26972f1431b85fba78e870b8d5f_StockbasedcompensationTextualDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_25d91085-ebf7-4866-958e-2ddce8ff0e30" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_NumberOfCommonSharesToBeReducedForEachStockOptionGranted_0abce899-c92a-4b83-bc5b-6f8363b1adfa" xlink:href="amgn-20201231.xsd#amgn_NumberOfCommonSharesToBeReducedForEachStockOptionGranted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_25d91085-ebf7-4866-958e-2ddce8ff0e30" xlink:to="loc_amgn_NumberOfCommonSharesToBeReducedForEachStockOptionGranted_0abce899-c92a-4b83-bc5b-6f8363b1adfa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_NumberOfCommonSharesToBeReducedForOtherTypesOfAwardsGranted_c389febb-0692-43e2-8c27-a49217a07f8b" xlink:href="amgn-20201231.xsd#amgn_NumberOfCommonSharesToBeReducedForOtherTypesOfAwardsGranted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_25d91085-ebf7-4866-958e-2ddce8ff0e30" xlink:to="loc_amgn_NumberOfCommonSharesToBeReducedForOtherTypesOfAwardsGranted_c389febb-0692-43e2-8c27-a49217a07f8b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_NumberofSharesAddedBackforTaxWithholdingonFullValueAwards_d2a802e7-327f-4236-b54f-c918d8f05bd9" xlink:href="amgn-20201231.xsd#amgn_NumberofSharesAddedBackforTaxWithholdingonFullValueAwards"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_25d91085-ebf7-4866-958e-2ddce8ff0e30" xlink:to="loc_amgn_NumberofSharesAddedBackforTaxWithholdingonFullValueAwards_d2a802e7-327f-4236-b54f-c918d8f05bd9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_AmountOfCommonStockAvailableUnderPlanForFutureGrantsAndOrIssuances_f3873952-9848-401e-b009-2def0f187bce" xlink:href="amgn-20201231.xsd#amgn_AmountOfCommonStockAvailableUnderPlanForFutureGrantsAndOrIssuances"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_25d91085-ebf7-4866-958e-2ddce8ff0e30" xlink:to="loc_amgn_AmountOfCommonStockAvailableUnderPlanForFutureGrantsAndOrIssuances_f3873952-9848-401e-b009-2def0f187bce" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingRights_2b601d50-f145-4113-bce2-1b4d9b931a39" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingRights"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_25d91085-ebf7-4866-958e-2ddce8ff0e30" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingRights_2b601d50-f145-4113-bce2-1b4d9b931a39" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_fe1bf2fd-f6ec-421a-ab6c-6dc9fd3e6232" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_25d91085-ebf7-4866-958e-2ddce8ff0e30" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_fe1bf2fd-f6ec-421a-ab6c-6dc9fd3e6232" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_204d12b2-f03b-412f-a379-71a56828b0e0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_25d91085-ebf7-4866-958e-2ddce8ff0e30" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_204d12b2-f03b-412f-a379-71a56828b0e0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_2587fb26-6a51-4acb-a787-aa8f295eebc1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_25d91085-ebf7-4866-958e-2ddce8ff0e30" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_2587fb26-6a51-4acb-a787-aa8f295eebc1" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_399eaf7e-6ffe-47af-8334-1fa72c1b26b8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_25d91085-ebf7-4866-958e-2ddce8ff0e30" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_399eaf7e-6ffe-47af-8334-1fa72c1b26b8" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_5570d8b8-777d-4048-934c-fccc1d8b1014" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_25d91085-ebf7-4866-958e-2ddce8ff0e30" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_5570d8b8-777d-4048-934c-fccc1d8b1014" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_e797be22-977a-424d-9c73-00f87e96b440" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_25d91085-ebf7-4866-958e-2ddce8ff0e30" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_e797be22-977a-424d-9c73-00f87e96b440" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromExerciseOfStockOptions_f56025a3-9dce-40b1-8c4a-0bb73a9605a1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromExerciseOfStockOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_25d91085-ebf7-4866-958e-2ddce8ff0e30" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromExerciseOfStockOptions_f56025a3-9dce-40b1-8c4a-0bb73a9605a1" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_c87c700e-8b2e-466d-9b1a-910baad7f08e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_25d91085-ebf7-4866-958e-2ddce8ff0e30" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_c87c700e-8b2e-466d-9b1a-910baad7f08e" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_NumberOfCommonSharesIssuedForEachPerformanceUnitEarned_14800bf3-caa8-4b48-bf22-47d2acf52d58" xlink:href="amgn-20201231.xsd#amgn_NumberOfCommonSharesIssuedForEachPerformanceUnitEarned"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_25d91085-ebf7-4866-958e-2ddce8ff0e30" xlink:to="loc_amgn_NumberOfCommonSharesIssuedForEachPerformanceUnitEarned_14800bf3-caa8-4b48-bf22-47d2acf52d58" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_008cd951-0d3e-4b78-ada4-174d12484add" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_25d91085-ebf7-4866-958e-2ddce8ff0e30" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_008cd951-0d3e-4b78-ada4-174d12484add" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_73b97b08-5fb9-453d-b976-7da5ff4e0a44" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_25d91085-ebf7-4866-958e-2ddce8ff0e30" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_73b97b08-5fb9-453d-b976-7da5ff4e0a44" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_6be01a81-f3b2-4800-ad44-941a0a346c33" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_25d91085-ebf7-4866-958e-2ddce8ff0e30" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_6be01a81-f3b2-4800-ad44-941a0a346c33" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_4835a08a-8aa5-41ad-afd4-c5c4046a7e9f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_25d91085-ebf7-4866-958e-2ddce8ff0e30" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_4835a08a-8aa5-41ad-afd4-c5c4046a7e9f" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_ddaa7f29-a0ee-45d1-82b6-869dda28c009" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_25d91085-ebf7-4866-958e-2ddce8ff0e30" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_ddaa7f29-a0ee-45d1-82b6-869dda28c009" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_d1e33e89-c588-4e08-be6d-5930c98899cd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_25d91085-ebf7-4866-958e-2ddce8ff0e30" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_d1e33e89-c588-4e08-be6d-5930c98899cd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_2571cef2-bef3-456c-9fdf-ebdd246cdd1f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_d1e33e89-c588-4e08-be6d-5930c98899cd" xlink:to="loc_us-gaap_AwardTypeAxis_2571cef2-bef3-456c-9fdf-ebdd246cdd1f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2571cef2-bef3-456c-9fdf-ebdd246cdd1f_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_2571cef2-bef3-456c-9fdf-ebdd246cdd1f" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2571cef2-bef3-456c-9fdf-ebdd246cdd1f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_36765888-d554-4d73-b4bc-3055fc5ddcf8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_2571cef2-bef3-456c-9fdf-ebdd246cdd1f" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_36765888-d554-4d73-b4bc-3055fc5ddcf8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_87af8e33-0a9b-4c3a-b4dd-15b813ec9fff" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_36765888-d554-4d73-b4bc-3055fc5ddcf8" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_87af8e33-0a9b-4c3a-b4dd-15b813ec9fff" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_b6efaded-add8-4276-9a23-c8647ddf937a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_36765888-d554-4d73-b4bc-3055fc5ddcf8" xlink:to="loc_us-gaap_EmployeeStockOptionMember_b6efaded-add8-4276-9a23-c8647ddf937a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_PerformanceUnitsMember_2082f823-e2e6-4aa1-a102-2314f0c09400" xlink:href="amgn-20201231.xsd#amgn_PerformanceUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_36765888-d554-4d73-b4bc-3055fc5ddcf8" xlink:to="loc_amgn_PerformanceUnitsMember_2082f823-e2e6-4aa1-a102-2314f0c09400" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/StockbasedcompensationComponentsofStockbasedCompensationExpenseDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#StockbasedcompensationComponentsofStockbasedCompensationExpenseDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/StockbasedcompensationComponentsofStockbasedCompensationExpenseDetails" xlink:type="extended" id="i264cb25d2b614c36ac745660413f48e3_StockbasedcompensationComponentsofStockbasedCompensationExpenseDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c97892e8-568c-481c-9a58-ad83e0f7a089" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationAbstract_7be507cc-ed5b-4562-83ab-9f09c3d94268" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c97892e8-568c-481c-9a58-ad83e0f7a089" xlink:to="loc_us-gaap_ShareBasedCompensationAbstract_7be507cc-ed5b-4562-83ab-9f09c3d94268" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensation_70414939-0dcc-44b8-9085-f098c3f08dcd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationAbstract_7be507cc-ed5b-4562-83ab-9f09c3d94268" xlink:to="loc_us-gaap_ShareBasedCompensation_70414939-0dcc-44b8-9085-f098c3f08dcd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_522eace6-1822-4028-8db3-5717c76fd39b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationAbstract_7be507cc-ed5b-4562-83ab-9f09c3d94268" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_522eace6-1822-4028-8db3-5717c76fd39b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_StockBasedCompensationExpenseNetOfTax_c7b0bd70-9f8f-4d5a-9c07-98c33d6723d7" xlink:href="amgn-20201231.xsd#amgn_StockBasedCompensationExpenseNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationAbstract_7be507cc-ed5b-4562-83ab-9f09c3d94268" xlink:to="loc_amgn_StockBasedCompensationExpenseNetOfTax_c7b0bd70-9f8f-4d5a-9c07-98c33d6723d7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_ca449d68-da63-4246-9595-4c4d5fe81976" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_c97892e8-568c-481c-9a58-ad83e0f7a089" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_ca449d68-da63-4246-9595-4c4d5fe81976" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_1819a46e-6000-4ed8-a758-bb8bc36d7964" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_ca449d68-da63-4246-9595-4c4d5fe81976" xlink:to="loc_us-gaap_AwardTypeAxis_1819a46e-6000-4ed8-a758-bb8bc36d7964" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1819a46e-6000-4ed8-a758-bb8bc36d7964_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_1819a46e-6000-4ed8-a758-bb8bc36d7964" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1819a46e-6000-4ed8-a758-bb8bc36d7964_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6659b2af-238e-4588-8194-22359bcfdd7a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_1819a46e-6000-4ed8-a758-bb8bc36d7964" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6659b2af-238e-4588-8194-22359bcfdd7a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_7e0677b7-9f2b-4131-b21b-16a0de863f02" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6659b2af-238e-4588-8194-22359bcfdd7a" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_7e0677b7-9f2b-4131-b21b-16a0de863f02" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_PerformanceUnitsMember_17271fac-f118-464b-9bf7-8e914306787f" xlink:href="amgn-20201231.xsd#amgn_PerformanceUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6659b2af-238e-4588-8194-22359bcfdd7a" xlink:to="loc_amgn_PerformanceUnitsMember_17271fac-f118-464b-9bf7-8e914306787f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_53473345-4dd6-44c2-8a88-0a3b8cd85174" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6659b2af-238e-4588-8194-22359bcfdd7a" xlink:to="loc_us-gaap_EmployeeStockOptionMember_53473345-4dd6-44c2-8a88-0a3b8cd85174" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/StockbasedcompensationSummaryofRSUsDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#StockbasedcompensationSummaryofRSUsDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/StockbasedcompensationSummaryofRSUsDetails" xlink:type="extended" id="i01a55af15d734310a1eacad1c29516bf_StockbasedcompensationSummaryofRSUsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_9b05c58d-891b-41ed-896c-6fea37a90588" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_60015633-d245-4376-9f31-2bbf186acc3e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_9b05c58d-891b-41ed-896c-6fea37a90588" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_60015633-d245-4376-9f31-2bbf186acc3e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_ac3dce8b-16e6-44c6-9b6f-c6a829c8af33" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_60015633-d245-4376-9f31-2bbf186acc3e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_ac3dce8b-16e6-44c6-9b6f-c6a829c8af33" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_b515185e-096a-4bc6-9d37-2052402b35c0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_60015633-d245-4376-9f31-2bbf186acc3e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_b515185e-096a-4bc6-9d37-2052402b35c0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_312d2521-0c84-4617-a13b-a60aedbf395c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_60015633-d245-4376-9f31-2bbf186acc3e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_312d2521-0c84-4617-a13b-a60aedbf395c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_343359bb-dea7-4c87-a79e-347f4b36fda7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_60015633-d245-4376-9f31-2bbf186acc3e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_343359bb-dea7-4c87-a79e-347f4b36fda7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_37abe796-7644-4da8-a0c9-bb735b203829" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_769cbb5f-67fe-4410-99a1-7e994133b4d1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_9b05c58d-891b-41ed-896c-6fea37a90588" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_769cbb5f-67fe-4410-99a1-7e994133b4d1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_190c4d43-a339-492b-846c-b2c7366fd51d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_769cbb5f-67fe-4410-99a1-7e994133b4d1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_190c4d43-a339-492b-846c-b2c7366fd51d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_1b290859-d079-45ff-b9d5-32d18601f7b1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_769cbb5f-67fe-4410-99a1-7e994133b4d1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_1b290859-d079-45ff-b9d5-32d18601f7b1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_4b0472cb-0a0c-4b91-b207-5d5a1cb152b8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_769cbb5f-67fe-4410-99a1-7e994133b4d1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_4b0472cb-0a0c-4b91-b207-5d5a1cb152b8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_12c30f88-0116-483c-a8a5-61f865b4c709" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_769cbb5f-67fe-4410-99a1-7e994133b4d1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_12c30f88-0116-483c-a8a5-61f865b4c709" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_bca62222-0cc7-4f6e-a5c2-a0b070e6154d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_2175c560-8c62-4dec-98aa-9885d0ef4836" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_9b05c58d-891b-41ed-896c-6fea37a90588" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_2175c560-8c62-4dec-98aa-9885d0ef4836" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_a495d144-4267-443d-8518-60582f8f59ed" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_2175c560-8c62-4dec-98aa-9885d0ef4836" xlink:to="loc_us-gaap_AwardTypeAxis_a495d144-4267-443d-8518-60582f8f59ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a495d144-4267-443d-8518-60582f8f59ed_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_a495d144-4267-443d-8518-60582f8f59ed" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a495d144-4267-443d-8518-60582f8f59ed_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f602f95d-f265-4ec9-97dc-8092e825fe2e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_a495d144-4267-443d-8518-60582f8f59ed" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f602f95d-f265-4ec9-97dc-8092e825fe2e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_823212e6-b919-4d82-ae9c-0400e053c172" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f602f95d-f265-4ec9-97dc-8092e825fe2e" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_823212e6-b919-4d82-ae9c-0400e053c172" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/StockbasedcompensationStockbasedcompensationSummaryofStockOptionsDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#StockbasedcompensationStockbasedcompensationSummaryofStockOptionsDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/StockbasedcompensationStockbasedcompensationSummaryofStockOptionsDetails" xlink:type="extended" id="i7fee4ff42669448595b98d2337e66866_StockbasedcompensationStockbasedcompensationSummaryofStockOptionsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_19944f81-449c-4568-a65e-8db1dd1e648b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CommonStockFairValue_1417b907-ab50-48ee-a83b-d061a3769750" xlink:href="amgn-20201231.xsd#amgn_CommonStockFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_19944f81-449c-4568-a65e-8db1dd1e648b" xlink:to="loc_amgn_CommonStockFairValue_1417b907-ab50-48ee-a83b-d061a3769750" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_81efa34a-0ca8-4851-bd9b-399a4a68d986" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_19944f81-449c-4568-a65e-8db1dd1e648b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_81efa34a-0ca8-4851-bd9b-399a4a68d986" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_e4c7c92a-17d4-422d-bd02-0e5c1b75c21d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_19944f81-449c-4568-a65e-8db1dd1e648b" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_e4c7c92a-17d4-422d-bd02-0e5c1b75c21d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_907f4172-6944-4551-bed7-4f9ad2c80624" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_19944f81-449c-4568-a65e-8db1dd1e648b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_907f4172-6944-4551-bed7-4f9ad2c80624" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_4727d44f-dd93-4e31-a6a1-4f4a38aced94" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_19944f81-449c-4568-a65e-8db1dd1e648b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_4727d44f-dd93-4e31-a6a1-4f4a38aced94" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_fefda351-69f4-420b-9d87-d59b8227fd27" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_19944f81-449c-4568-a65e-8db1dd1e648b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_fefda351-69f4-420b-9d87-d59b8227fd27" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_7727e0d1-fa6b-4e71-93c2-bd26e3cf78d4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_19944f81-449c-4568-a65e-8db1dd1e648b" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_7727e0d1-fa6b-4e71-93c2-bd26e3cf78d4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_ec54c481-55e7-4a10-9da9-32dbb9647cca" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_7727e0d1-fa6b-4e71-93c2-bd26e3cf78d4" xlink:to="loc_us-gaap_AwardTypeAxis_ec54c481-55e7-4a10-9da9-32dbb9647cca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ec54c481-55e7-4a10-9da9-32dbb9647cca_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_ec54c481-55e7-4a10-9da9-32dbb9647cca" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ec54c481-55e7-4a10-9da9-32dbb9647cca_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d98a12d0-2c24-4b1d-89d8-c518439c5c9e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_ec54c481-55e7-4a10-9da9-32dbb9647cca" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d98a12d0-2c24-4b1d-89d8-c518439c5c9e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_a0c47649-4d65-4f41-9040-d148061e78be" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d98a12d0-2c24-4b1d-89d8-c518439c5c9e" xlink:to="loc_us-gaap_EmployeeStockOptionMember_a0c47649-4d65-4f41-9040-d148061e78be" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/StockbasedcompensationSummaryofStockOptionsDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#StockbasedcompensationSummaryofStockOptionsDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/StockbasedcompensationSummaryofStockOptionsDetails" xlink:type="extended" id="ib0a959bc0ef940c7a73c96317e414557_StockbasedcompensationSummaryofStockOptionsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7489d810-4295-409b-b63f-3c8aad54f451" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_a550e512-f7bd-4ecd-9bca-76a424db357d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7489d810-4295-409b-b63f-3c8aad54f451" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_a550e512-f7bd-4ecd-9bca-76a424db357d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_2abd9492-d0ac-49ae-99c8-a897746b4a12" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_a550e512-f7bd-4ecd-9bca-76a424db357d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_2abd9492-d0ac-49ae-99c8-a897746b4a12" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod_1b819552-4154-478c-a5af-1293deec3716" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_a550e512-f7bd-4ecd-9bca-76a424db357d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod_1b819552-4154-478c-a5af-1293deec3716" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_d6ec8e97-0a99-42fd-84b3-8ef3c18838ee" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_a550e512-f7bd-4ecd-9bca-76a424db357d" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_d6ec8e97-0a99-42fd-84b3-8ef3c18838ee" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod_ae558ad8-25a5-498d-b452-265435310f16" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_a550e512-f7bd-4ecd-9bca-76a424db357d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod_ae558ad8-25a5-498d-b452-265435310f16" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_ff1ce46f-6643-4093-b393-dc3222321362" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber_0d2f12f9-2e24-44e5-aa4c-28fcdec8dc8e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7489d810-4295-409b-b63f-3c8aad54f451" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber_0d2f12f9-2e24-44e5-aa4c-28fcdec8dc8e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_3dac17d9-d62a-4960-b6e7-edfa46b08c3e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7489d810-4295-409b-b63f-3c8aad54f451" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_3dac17d9-d62a-4960-b6e7-edfa46b08c3e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_dcf71e4a-b7bf-4499-bda6-84b7d9ebb022" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7489d810-4295-409b-b63f-3c8aad54f451" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_dcf71e4a-b7bf-4499-bda6-84b7d9ebb022" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_f306901f-293c-4aa8-bafb-72a7b089b46c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_dcf71e4a-b7bf-4499-bda6-84b7d9ebb022" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_f306901f-293c-4aa8-bafb-72a7b089b46c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_d8d36475-555d-417c-a507-8b6413e669c8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_dcf71e4a-b7bf-4499-bda6-84b7d9ebb022" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_d8d36475-555d-417c-a507-8b6413e669c8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_ee2684ee-3f2c-4f85-9310-8a534467a65a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_dcf71e4a-b7bf-4499-bda6-84b7d9ebb022" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_ee2684ee-3f2c-4f85-9310-8a534467a65a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice_97b692d1-482f-4453-85f3-b6f0b0d603b7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_dcf71e4a-b7bf-4499-bda6-84b7d9ebb022" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice_97b692d1-482f-4453-85f3-b6f0b0d603b7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_b4553b7f-2975-434a-a02a-d2dcb36e813a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice_b6ce52a7-8efd-458a-aaec-a88f0ad59924" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7489d810-4295-409b-b63f-3c8aad54f451" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice_b6ce52a7-8efd-458a-aaec-a88f0ad59924" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_30227a3f-982f-42f2-be9c-803f0a9f7ada" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7489d810-4295-409b-b63f-3c8aad54f451" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_30227a3f-982f-42f2-be9c-803f0a9f7ada" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_320d4a9a-7c5e-482d-8dcc-97ca15f61eaf" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7489d810-4295-409b-b63f-3c8aad54f451" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_320d4a9a-7c5e-482d-8dcc-97ca15f61eaf" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_eccb9021-653d-4fcb-aa3d-4115abbae538" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_320d4a9a-7c5e-482d-8dcc-97ca15f61eaf" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_eccb9021-653d-4fcb-aa3d-4115abbae538" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1_d6b125be-f216-4c66-b082-f5341b818809" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_320d4a9a-7c5e-482d-8dcc-97ca15f61eaf" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1_d6b125be-f216-4c66-b082-f5341b818809" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_f2021d9b-676a-4163-b661-082b589936f6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_320d4a9a-7c5e-482d-8dcc-97ca15f61eaf" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_f2021d9b-676a-4163-b661-082b589936f6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_6584f16f-ff8c-406e-a509-eaa42c2066c8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_320d4a9a-7c5e-482d-8dcc-97ca15f61eaf" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_6584f16f-ff8c-406e-a509-eaa42c2066c8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue_c5b3bb38-b3c9-4c05-99b2-2a8dd400d70f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_320d4a9a-7c5e-482d-8dcc-97ca15f61eaf" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue_c5b3bb38-b3c9-4c05-99b2-2a8dd400d70f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1_15f1fa3a-5ae4-49f7-bede-87228dd293f9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_320d4a9a-7c5e-482d-8dcc-97ca15f61eaf" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1_15f1fa3a-5ae4-49f7-bede-87228dd293f9" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1faa6676-3f15-47f3-b684-19a085b75de9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_7489d810-4295-409b-b63f-3c8aad54f451" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1faa6676-3f15-47f3-b684-19a085b75de9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_f1309c57-c663-4328-90c9-122594cf98fa" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1faa6676-3f15-47f3-b684-19a085b75de9" xlink:to="loc_us-gaap_AwardTypeAxis_f1309c57-c663-4328-90c9-122594cf98fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f1309c57-c663-4328-90c9-122594cf98fa_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_f1309c57-c663-4328-90c9-122594cf98fa" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f1309c57-c663-4328-90c9-122594cf98fa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ffd30ca8-ded8-47e7-95aa-c182908f608d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_f1309c57-c663-4328-90c9-122594cf98fa" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ffd30ca8-ded8-47e7-95aa-c182908f608d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_e8bd225c-b349-4838-999c-0f0a7acf1e2b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ffd30ca8-ded8-47e7-95aa-c182908f608d" xlink:to="loc_us-gaap_EmployeeStockOptionMember_e8bd225c-b349-4838-999c-0f0a7acf1e2b" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/StockbasedcompensationWeightedaverageAssumptionsDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#StockbasedcompensationWeightedaverageAssumptionsDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/StockbasedcompensationWeightedaverageAssumptionsDetails" xlink:type="extended" id="i1ec894b47c454033913d0225f630ce16_StockbasedcompensationWeightedaverageAssumptionsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f281a66b-c049-466c-9a3c-8e0c38c3860d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_ade8b8b3-c393-481c-9b49-353590c2b772" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f281a66b-c049-466c-9a3c-8e0c38c3860d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_ade8b8b3-c393-481c-9b49-353590c2b772" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CommonStockFairValue_5cd96715-d30c-4ec9-bbdc-5ed85479f379" xlink:href="amgn-20201231.xsd#amgn_CommonStockFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_ade8b8b3-c393-481c-9b49-353590c2b772" xlink:to="loc_amgn_CommonStockFairValue_5cd96715-d30c-4ec9-bbdc-5ed85479f379" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_aa818743-cb65-44bc-8cd9-262d831249b5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_ade8b8b3-c393-481c-9b49-353590c2b772" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_aa818743-cb65-44bc-8cd9-262d831249b5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_13ecacf6-3565-49e3-a81e-0e2a7dbb81c3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_ade8b8b3-c393-481c-9b49-353590c2b772" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_13ecacf6-3565-49e3-a81e-0e2a7dbb81c3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_da724ab0-e7f9-4248-9cf8-7191c5b25748" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_ade8b8b3-c393-481c-9b49-353590c2b772" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_da724ab0-e7f9-4248-9cf8-7191c5b25748" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0db2528e-2317-4c52-8d94-18237e36bb65" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f281a66b-c049-466c-9a3c-8e0c38c3860d" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0db2528e-2317-4c52-8d94-18237e36bb65" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_6f65612f-2b1a-435a-9e04-971ed4668dec" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0db2528e-2317-4c52-8d94-18237e36bb65" xlink:to="loc_us-gaap_AwardTypeAxis_6f65612f-2b1a-435a-9e04-971ed4668dec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6f65612f-2b1a-435a-9e04-971ed4668dec_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_6f65612f-2b1a-435a-9e04-971ed4668dec" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6f65612f-2b1a-435a-9e04-971ed4668dec_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_78f62c7b-0f03-429f-bd47-69e8558c8474" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_6f65612f-2b1a-435a-9e04-971ed4668dec" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_78f62c7b-0f03-429f-bd47-69e8558c8474" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_PerformanceUnitsMember_06efd60f-8904-4808-98be-4f9307568cbe" xlink:href="amgn-20201231.xsd#amgn_PerformanceUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_78f62c7b-0f03-429f-bd47-69e8558c8474" xlink:to="loc_amgn_PerformanceUnitsMember_06efd60f-8904-4808-98be-4f9307568cbe" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/Definedcontributionplan" xlink:type="simple" xlink:href="amgn-20201231.xsd#Definedcontributionplan"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/Definedcontributionplan" xlink:type="extended" id="i8c5beaa35c8740dd8bd362cb5924b136_Definedcontributionplan"/>
  <link:roleRef roleURI="http://www.amgen.com/role/DefinedcontributionplanDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#DefinedcontributionplanDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/DefinedcontributionplanDetails" xlink:type="extended" id="ia9596117090f4ab496918656d3f7f677_DefinedcontributionplanDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/Incometaxes" xlink:type="simple" xlink:href="amgn-20201231.xsd#Incometaxes"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/Incometaxes" xlink:type="extended" id="i600815db33ea40698942f24783c3ad9c_Incometaxes"/>
  <link:roleRef roleURI="http://www.amgen.com/role/IncometaxesTables" xlink:type="simple" xlink:href="amgn-20201231.xsd#IncometaxesTables"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/IncometaxesTables" xlink:type="extended" id="ica45f84c08c140b2968b50e6829c883e_IncometaxesTables"/>
  <link:roleRef roleURI="http://www.amgen.com/role/IncometaxesIncomeBeforeIncomeTaxesDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#IncometaxesIncomeBeforeIncomeTaxesDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/IncometaxesIncomeBeforeIncomeTaxesDetails" xlink:type="extended" id="ic46d814bbf824a45a7258bd8be7fb6d8_IncometaxesIncomeBeforeIncomeTaxesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExaminationLineItems_6b6f32ee-3f3a-4be5-a97a-682771383c9a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExaminationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_fd414b69-abf8-43fe-8954-531256db6887" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_6b6f32ee-3f3a-4be5-a97a-682771383c9a" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_fd414b69-abf8-43fe-8954-531256db6887" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExaminationTable_a3de7bd9-c14b-4242-82df-7a1df50c4da1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExaminationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeTaxExaminationLineItems_6b6f32ee-3f3a-4be5-a97a-682771383c9a" xlink:to="loc_us-gaap_IncomeTaxExaminationTable_a3de7bd9-c14b-4242-82df-7a1df50c4da1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_d956eaf8-06d1-4fcb-9f2b-4c456600f32c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeTaxExaminationTable_a3de7bd9-c14b-4242-82df-7a1df50c4da1" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_d956eaf8-06d1-4fcb-9f2b-4c456600f32c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_d956eaf8-06d1-4fcb-9f2b-4c456600f32c_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_d956eaf8-06d1-4fcb-9f2b-4c456600f32c" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_d956eaf8-06d1-4fcb-9f2b-4c456600f32c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_1424881e-ed93-45a4-94ff-3effc6cac0d4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_d956eaf8-06d1-4fcb-9f2b-4c456600f32c" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_1424881e-ed93-45a4-94ff-3effc6cac0d4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DomesticCountryMember_aa5626e5-f47e-40a8-85f4-8e8dd1ec2e03" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DomesticCountryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_1424881e-ed93-45a4-94ff-3effc6cac0d4" xlink:to="loc_us-gaap_DomesticCountryMember_aa5626e5-f47e-40a8-85f4-8e8dd1ec2e03" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCountryMember_0390c886-48d2-4c46-b6da-b57db846407a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ForeignCountryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_1424881e-ed93-45a4-94ff-3effc6cac0d4" xlink:to="loc_us-gaap_ForeignCountryMember_0390c886-48d2-4c46-b6da-b57db846407a" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/IncometaxesProvisionforIncomeTaxesDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#IncometaxesProvisionforIncomeTaxesDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/IncometaxesProvisionforIncomeTaxesDetails" xlink:type="extended" id="i363e3286614b40c885386e16be22712c_IncometaxesProvisionforIncomeTaxesDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/IncometaxesComponentsofDeferredTaxAssetsandLiabilitiesDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#IncometaxesComponentsofDeferredTaxAssetsandLiabilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/IncometaxesComponentsofDeferredTaxAssetsandLiabilitiesDetails" xlink:type="extended" id="ifc87963e128249e9aa3223d38deebf65_IncometaxesComponentsofDeferredTaxAssetsandLiabilitiesDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/IncometaxesTextualDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#IncometaxesTextualDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/IncometaxesTextualDetails" xlink:type="extended" id="i7958a94f8a5a4095a27770fd49b65aef_IncometaxesTextualDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxCreditCarryforwardLineItems_0889e13a-9e57-42cb-9bbb-7ff50716ee76" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxCreditCarryforwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxCreditCarryforwardAmount_134996dc-7560-4a30-9574-629a3077e4e1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxCreditCarryforwardAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxCreditCarryforwardLineItems_0889e13a-9e57-42cb-9bbb-7ff50716ee76" xlink:to="loc_us-gaap_TaxCreditCarryforwardAmount_134996dc-7560-4a30-9574-629a3077e4e1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxCreditCarryforwardValuationAllowance_61dec333-ba3e-4e51-aeee-f3c6f3349168" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxCreditCarryforwardValuationAllowance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxCreditCarryforwardLineItems_0889e13a-9e57-42cb-9bbb-7ff50716ee76" xlink:to="loc_us-gaap_TaxCreditCarryforwardValuationAllowance_61dec333-ba3e-4e51-aeee-f3c6f3349168" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwards_835d532e-87f7-4d40-b654-0187813cc546" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLossCarryforwards"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxCreditCarryforwardLineItems_0889e13a-9e57-42cb-9bbb-7ff50716ee76" xlink:to="loc_us-gaap_OperatingLossCarryforwards_835d532e-87f7-4d40-b654-0187813cc546" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwardsValuationAllowance_30972823-136b-4ae3-b7f3-1fffddca290b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLossCarryforwardsValuationAllowance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxCreditCarryforwardLineItems_0889e13a-9e57-42cb-9bbb-7ff50716ee76" xlink:to="loc_us-gaap_OperatingLossCarryforwardsValuationAllowance_30972823-136b-4ae3-b7f3-1fffddca290b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsNotSubjectToExpiration_750e3157-3ba2-4490-8dba-28be48cc2dab" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsNotSubjectToExpiration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxCreditCarryforwardLineItems_0889e13a-9e57-42cb-9bbb-7ff50716ee76" xlink:to="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsNotSubjectToExpiration_750e3157-3ba2-4490-8dba-28be48cc2dab" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense_c8b724b1-fe58-4e5d-b3a7-e917d4d277cf" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxCreditCarryforwardLineItems_0889e13a-9e57-42cb-9bbb-7ff50716ee76" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense_c8b724b1-fe58-4e5d-b3a7-e917d4d277cf" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued_6950710c-c462-46a3-bffc-ac071fed33a2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxCreditCarryforwardLineItems_0889e13a-9e57-42cb-9bbb-7ff50716ee76" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued_6950710c-c462-46a3-bffc-ac071fed33a2" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxesPaid_53133ae5-1a72-4d13-b002-2a54aad67ffe" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxesPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxCreditCarryforwardLineItems_0889e13a-9e57-42cb-9bbb-7ff50716ee76" xlink:to="loc_us-gaap_IncomeTaxesPaid_53133ae5-1a72-4d13-b002-2a54aad67ffe" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxCreditCarryforwardTable_dcea6516-d0fb-48fe-8f11-7557eb4b0087" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxCreditCarryforwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_TaxCreditCarryforwardLineItems_0889e13a-9e57-42cb-9bbb-7ff50716ee76" xlink:to="loc_us-gaap_TaxCreditCarryforwardTable_dcea6516-d0fb-48fe-8f11-7557eb4b0087" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_e71a1314-cc7f-4714-aa13-b4cf3aa4add3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_TaxCreditCarryforwardTable_dcea6516-d0fb-48fe-8f11-7557eb4b0087" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_e71a1314-cc7f-4714-aa13-b4cf3aa4add3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_e71a1314-cc7f-4714-aa13-b4cf3aa4add3_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_e71a1314-cc7f-4714-aa13-b4cf3aa4add3" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_e71a1314-cc7f-4714-aa13-b4cf3aa4add3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_16f67e18-041d-4dfe-bfc1-e20bb86ddfc3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_e71a1314-cc7f-4714-aa13-b4cf3aa4add3" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_16f67e18-041d-4dfe-bfc1-e20bb86ddfc3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DomesticCountryMember_4ab1b363-9c5b-4ad9-9cba-75369285ade1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DomesticCountryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_16f67e18-041d-4dfe-bfc1-e20bb86ddfc3" xlink:to="loc_us-gaap_DomesticCountryMember_4ab1b363-9c5b-4ad9-9cba-75369285ade1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StateAndLocalJurisdictionMember_089e7c09-0903-4642-ad28-0a3bcc273231" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StateAndLocalJurisdictionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_16f67e18-041d-4dfe-bfc1-e20bb86ddfc3" xlink:to="loc_us-gaap_StateAndLocalJurisdictionMember_089e7c09-0903-4642-ad28-0a3bcc273231" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCountryMember_565ae4a7-fe59-4b55-a5c8-f26941603f01" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ForeignCountryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_16f67e18-041d-4dfe-bfc1-e20bb86ddfc3" xlink:to="loc_us-gaap_ForeignCountryMember_565ae4a7-fe59-4b55-a5c8-f26941603f01" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxPeriodAxis_32082435-0f91-40f4-878c-5321d60bef8b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxPeriodAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_TaxCreditCarryforwardTable_dcea6516-d0fb-48fe-8f11-7557eb4b0087" xlink:to="loc_us-gaap_TaxPeriodAxis_32082435-0f91-40f4-878c-5321d60bef8b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxPeriodDomain_32082435-0f91-40f4-878c-5321d60bef8b_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TaxPeriodAxis_32082435-0f91-40f4-878c-5321d60bef8b" xlink:to="loc_us-gaap_TaxPeriodDomain_32082435-0f91-40f4-878c-5321d60bef8b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxPeriodDomain_ecb42ca8-ab70-4dbe-b644-c92342bad475" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TaxPeriodAxis_32082435-0f91-40f4-878c-5321d60bef8b" xlink:to="loc_us-gaap_TaxPeriodDomain_ecb42ca8-ab70-4dbe-b644-c92342bad475" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_OperatingLossesThatExpireBetween2021And2035Member_02cb72d7-991b-4533-894e-49165489aaeb" xlink:href="amgn-20201231.xsd#amgn_OperatingLossesThatExpireBetween2021And2035Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxPeriodDomain_ecb42ca8-ab70-4dbe-b644-c92342bad475" xlink:to="loc_amgn_OperatingLossesThatExpireBetween2021And2035Member_02cb72d7-991b-4533-894e-49165489aaeb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_OperatingLossesThatExpireBetween2021And2030Member_c8c2e6e7-298f-4fc5-840b-19b661dd04bf" xlink:href="amgn-20201231.xsd#amgn_OperatingLossesThatExpireBetween2021And2030Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxPeriodDomain_ecb42ca8-ab70-4dbe-b644-c92342bad475" xlink:to="loc_amgn_OperatingLossesThatExpireBetween2021And2030Member_c8c2e6e7-298f-4fc5-840b-19b661dd04bf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ExpirationInTaxYearsBetween2023And2035Member_c9ca9261-5d71-4f54-bde6-cfc6fef787ef" xlink:href="amgn-20201231.xsd#amgn_ExpirationInTaxYearsBetween2023And2035Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxPeriodDomain_ecb42ca8-ab70-4dbe-b644-c92342bad475" xlink:to="loc_amgn_ExpirationInTaxYearsBetween2023And2035Member_c9ca9261-5d71-4f54-bde6-cfc6fef787ef" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/IncometaxesReconciliationofTotalGrossAmountsofUTBsDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#IncometaxesReconciliationofTotalGrossAmountsofUTBsDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/IncometaxesReconciliationofTotalGrossAmountsofUTBsDetails" xlink:type="extended" id="ia10480c2552f4419857b490db1d4f853_IncometaxesReconciliationofTotalGrossAmountsofUTBsDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/IncometaxesReconciliationofFederalStatutoryTaxRateDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#IncometaxesReconciliationofFederalStatutoryTaxRateDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/IncometaxesReconciliationofFederalStatutoryTaxRateDetails" xlink:type="extended" id="i85fef8b7745949d99eeece19b1c91be1_IncometaxesReconciliationofFederalStatutoryTaxRateDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/Earningspershare" xlink:type="simple" xlink:href="amgn-20201231.xsd#Earningspershare"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/Earningspershare" xlink:type="extended" id="i960f32a944c24b798715dc598ff10cdf_Earningspershare"/>
  <link:roleRef roleURI="http://www.amgen.com/role/EarningspershareTables" xlink:type="simple" xlink:href="amgn-20201231.xsd#EarningspershareTables"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/EarningspershareTables" xlink:type="extended" id="if23179283df44068856e111037531938_EarningspershareTables"/>
  <link:roleRef roleURI="http://www.amgen.com/role/EarningspershareDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#EarningspershareDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/EarningspershareDetails" xlink:type="extended" id="i4452cb5612d84a7680f9d75c71eb9378_EarningspershareDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/Collaborations" xlink:type="simple" xlink:href="amgn-20201231.xsd#Collaborations"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/Collaborations" xlink:type="extended" id="i502ae20768dd43c4b921bdea962073c5_Collaborations"/>
  <link:roleRef roleURI="http://www.amgen.com/role/CollaborationsNovartisAGDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#CollaborationsNovartisAGDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/CollaborationsNovartisAGDetails" xlink:type="extended" id="i25e30d94adc24c719f18d4a6a17fce10_CollaborationsNovartisAGDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_6f2bde64-e839-4330-8741-e421a9fe5dc6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_RevenueRecognitionMilestoneMethodPotentialFutureMilestonePayment_77169837-7eb0-4bf1-b7a0-19c6e91c23df" xlink:href="amgn-20201231.xsd#amgn_RevenueRecognitionMilestoneMethodPotentialFutureMilestonePayment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_6f2bde64-e839-4330-8741-e421a9fe5dc6" xlink:to="loc_amgn_RevenueRecognitionMilestoneMethodPotentialFutureMilestonePayment_77169837-7eb0-4bf1-b7a0-19c6e91c23df" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DirectOperatingCosts_0b637e5b-04fd-4822-8d84-7e2aa1b9e3e9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DirectOperatingCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_6f2bde64-e839-4330-8741-e421a9fe5dc6" xlink:to="loc_us-gaap_DirectOperatingCosts_0b637e5b-04fd-4822-8d84-7e2aa1b9e3e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RecoveryOfDirectCosts_09372c16-19cb-4e02-9947-7843880171ed" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RecoveryOfDirectCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_6f2bde64-e839-4330-8741-e421a9fe5dc6" xlink:to="loc_us-gaap_RecoveryOfDirectCosts_09372c16-19cb-4e02-9947-7843880171ed" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RoyaltyExpense_b47c9985-e9e5-4901-b9f7-f21af0b676a2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RoyaltyExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_6f2bde64-e839-4330-8741-e421a9fe5dc6" xlink:to="loc_us-gaap_RoyaltyExpense_b47c9985-e9e5-4901-b9f7-f21af0b676a2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_f4ddad75-2c12-4208-b5a5-b827e258b4cb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_6f2bde64-e839-4330-8741-e421a9fe5dc6" xlink:to="loc_us-gaap_Revenues_f4ddad75-2c12-4208-b5a5-b827e258b4cb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_2b4ce487-7828-4d49-9cd5-36af59328870" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_6f2bde64-e839-4330-8741-e421a9fe5dc6" xlink:to="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_2b4ce487-7828-4d49-9cd5-36af59328870" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfArrangementAxis_f986da10-6a5d-4afc-a07e-8c38b5bdcc0c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfArrangementAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_2b4ce487-7828-4d49-9cd5-36af59328870" xlink:to="loc_us-gaap_TypeOfArrangementAxis_f986da10-6a5d-4afc-a07e-8c38b5bdcc0c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_f986da10-6a5d-4afc-a07e-8c38b5bdcc0c_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TypeOfArrangementAxis_f986da10-6a5d-4afc-a07e-8c38b5bdcc0c" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_f986da10-6a5d-4afc-a07e-8c38b5bdcc0c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_c738a416-d298-4289-ab8b-6e6bf40c2b22" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TypeOfArrangementAxis_f986da10-6a5d-4afc-a07e-8c38b5bdcc0c" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_c738a416-d298-4289-ab8b-6e6bf40c2b22" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CollaborativeArrangementwithNovartisPharmaAGMember_f2b1023e-e1da-4f23-b89d-33ec0864b4e5" xlink:href="amgn-20201231.xsd#amgn_CollaborativeArrangementwithNovartisPharmaAGMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_c738a416-d298-4289-ab8b-6e6bf40c2b22" xlink:to="loc_amgn_CollaborativeArrangementwithNovartisPharmaAGMember_f2b1023e-e1da-4f23-b89d-33ec0864b4e5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_bf0253ab-7fdc-468c-9818-487c8acc7b8f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_2b4ce487-7828-4d49-9cd5-36af59328870" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_bf0253ab-7fdc-468c-9818-487c8acc7b8f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_bf0253ab-7fdc-468c-9818-487c8acc7b8f_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_bf0253ab-7fdc-468c-9818-487c8acc7b8f" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_bf0253ab-7fdc-468c-9818-487c8acc7b8f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_9f2312e8-df29-49e0-8316-692c12c86e73" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_bf0253ab-7fdc-468c-9818-487c8acc7b8f" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_9f2312e8-df29-49e0-8316-692c12c86e73" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_af99b493-aa08-48fa-8f83-e6f99e0fb923" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_9f2312e8-df29-49e0-8316-692c12c86e73" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_af99b493-aa08-48fa-8f83-e6f99e0fb923" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfSalesMember_4d3ea7a9-80b6-4cd1-beeb-8484b9e6a451" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CostOfSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_9f2312e8-df29-49e0-8316-692c12c86e73" xlink:to="loc_us-gaap_CostOfSalesMember_4d3ea7a9-80b6-4cd1-beeb-8484b9e6a451" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_c02b83ca-d4d1-40a0-94b5-b7acef601d7f" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_2b4ce487-7828-4d49-9cd5-36af59328870" xlink:to="loc_srt_ProductOrServiceAxis_c02b83ca-d4d1-40a0-94b5-b7acef601d7f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_c02b83ca-d4d1-40a0-94b5-b7acef601d7f_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_c02b83ca-d4d1-40a0-94b5-b7acef601d7f" xlink:to="loc_srt_ProductsAndServicesDomain_c02b83ca-d4d1-40a0-94b5-b7acef601d7f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_22b07714-7e82-40f4-a0ce-caaff9e9bd24" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_c02b83ca-d4d1-40a0-94b5-b7acef601d7f" xlink:to="loc_srt_ProductsAndServicesDomain_22b07714-7e82-40f4-a0ce-caaff9e9bd24" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductAndServiceOtherMember_9aa7d0f6-e5e3-4ccf-b3bf-4c377cf31738" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProductAndServiceOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_22b07714-7e82-40f4-a0ce-caaff9e9bd24" xlink:to="loc_us-gaap_ProductAndServiceOtherMember_9aa7d0f6-e5e3-4ccf-b3bf-4c377cf31738" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/CollaborationsBayerHealthCarePharmaceuticalsIncDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#CollaborationsBayerHealthCarePharmaceuticalsIncDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/CollaborationsBayerHealthCarePharmaceuticalsIncDetails" xlink:type="extended" id="i80111a73dbc547488869d38caf87d18e_CollaborationsBayerHealthCarePharmaceuticalsIncDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_d3ffceab-fb86-4512-80e8-59ca86e68805" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_NumberofCountriesProductsisMarketedandSold_5e69e012-67c1-4098-be09-97c482d4fad9" xlink:href="amgn-20201231.xsd#amgn_NumberofCountriesProductsisMarketedandSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_d3ffceab-fb86-4512-80e8-59ca86e68805" xlink:to="loc_amgn_NumberofCountriesProductsisMarketedandSold_5e69e012-67c1-4098-be09-97c482d4fad9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CollaborativeArrangementRoyaltyIncomePercentage_ca2b8f05-3f90-463d-9def-66162a9b929e" xlink:href="amgn-20201231.xsd#amgn_CollaborativeArrangementRoyaltyIncomePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_d3ffceab-fb86-4512-80e8-59ca86e68805" xlink:to="loc_amgn_CollaborativeArrangementRoyaltyIncomePercentage_ca2b8f05-3f90-463d-9def-66162a9b929e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CollaborativeArrangementNetIncome_ff1e5405-11ea-4488-9f04-e2f67df09a3e" xlink:href="amgn-20201231.xsd#amgn_CollaborativeArrangementNetIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_d3ffceab-fb86-4512-80e8-59ca86e68805" xlink:to="loc_amgn_CollaborativeArrangementNetIncome_ff1e5405-11ea-4488-9f04-e2f67df09a3e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_2f2f44f8-d415-43a1-9761-512ce1148249" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_d3ffceab-fb86-4512-80e8-59ca86e68805" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_2f2f44f8-d415-43a1-9761-512ce1148249" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_446e5d79-b10b-43ca-84b5-c72bff24c106" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_d3ffceab-fb86-4512-80e8-59ca86e68805" xlink:to="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_446e5d79-b10b-43ca-84b5-c72bff24c106" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfArrangementAxis_87c7292f-0a5e-4f43-94de-591add61f0a9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfArrangementAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_446e5d79-b10b-43ca-84b5-c72bff24c106" xlink:to="loc_us-gaap_TypeOfArrangementAxis_87c7292f-0a5e-4f43-94de-591add61f0a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_87c7292f-0a5e-4f43-94de-591add61f0a9_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TypeOfArrangementAxis_87c7292f-0a5e-4f43-94de-591add61f0a9" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_87c7292f-0a5e-4f43-94de-591add61f0a9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_def072b9-899f-4ebd-971a-3c508e8e4db7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TypeOfArrangementAxis_87c7292f-0a5e-4f43-94de-591add61f0a9" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_def072b9-899f-4ebd-971a-3c508e8e4db7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CollaborativeArrangementswithBayerHealthCarePharmaceuticalsInc.Member_3510caff-3872-474b-bd40-10ed7bdfebca" xlink:href="amgn-20201231.xsd#amgn_CollaborativeArrangementswithBayerHealthCarePharmaceuticalsInc.Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_def072b9-899f-4ebd-971a-3c508e8e4db7" xlink:to="loc_amgn_CollaborativeArrangementswithBayerHealthCarePharmaceuticalsInc.Member_3510caff-3872-474b-bd40-10ed7bdfebca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_56ab7f52-7dc0-4e67-8998-96c59ca6d9eb" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_446e5d79-b10b-43ca-84b5-c72bff24c106" xlink:to="loc_srt_ProductOrServiceAxis_56ab7f52-7dc0-4e67-8998-96c59ca6d9eb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_56ab7f52-7dc0-4e67-8998-96c59ca6d9eb_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_56ab7f52-7dc0-4e67-8998-96c59ca6d9eb" xlink:to="loc_srt_ProductsAndServicesDomain_56ab7f52-7dc0-4e67-8998-96c59ca6d9eb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_05cc00ec-ca3d-4111-9b13-eaf5911a0949" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_56ab7f52-7dc0-4e67-8998-96c59ca6d9eb" xlink:to="loc_srt_ProductsAndServicesDomain_05cc00ec-ca3d-4111-9b13-eaf5911a0949" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_NexavarMember_57a4314a-5371-4420-a5b7-b4f050836f7e" xlink:href="amgn-20201231.xsd#amgn_NexavarMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_05cc00ec-ca3d-4111-9b13-eaf5911a0949" xlink:to="loc_amgn_NexavarMember_57a4314a-5371-4420-a5b7-b4f050836f7e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RoyaltyMember_97c15cec-dcb5-43b9-a096-a5eebf8dec48" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RoyaltyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_05cc00ec-ca3d-4111-9b13-eaf5911a0949" xlink:to="loc_us-gaap_RoyaltyMember_97c15cec-dcb5-43b9-a096-a5eebf8dec48" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_5fb95dd1-a4cb-4990-a3ea-e536c7388c1a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_446e5d79-b10b-43ca-84b5-c72bff24c106" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_5fb95dd1-a4cb-4990-a3ea-e536c7388c1a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_5fb95dd1-a4cb-4990-a3ea-e536c7388c1a_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_5fb95dd1-a4cb-4990-a3ea-e536c7388c1a" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_5fb95dd1-a4cb-4990-a3ea-e536c7388c1a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_ca17b1f4-6ad3-482c-b3ac-28d717ca170d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_5fb95dd1-a4cb-4990-a3ea-e536c7388c1a" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_ca17b1f4-6ad3-482c-b3ac-28d717ca170d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_OtherRevenuesMember_8aa02890-2137-472a-96fb-60e1b604c5ae" xlink:href="amgn-20201231.xsd#amgn_OtherRevenuesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_ca17b1f4-6ad3-482c-b3ac-28d717ca170d" xlink:to="loc_amgn_OtherRevenuesMember_8aa02890-2137-472a-96fb-60e1b604c5ae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_be198243-dca9-479d-951d-ea87d4162bd2" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_446e5d79-b10b-43ca-84b5-c72bff24c106" xlink:to="loc_srt_StatementGeographicalAxis_be198243-dca9-479d-951d-ea87d4162bd2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_be198243-dca9-479d-951d-ea87d4162bd2_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_be198243-dca9-479d-951d-ea87d4162bd2" xlink:to="loc_srt_SegmentGeographicalDomain_be198243-dca9-479d-951d-ea87d4162bd2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_8082c23b-a50d-492e-a26c-fb24eaa19254" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_be198243-dca9-479d-951d-ea87d4162bd2" xlink:to="loc_srt_SegmentGeographicalDomain_8082c23b-a50d-492e-a26c-fb24eaa19254" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_216bc4d5-bec8-4061-ae3b-12acdd88718d" xlink:href="https://xbrl.sec.gov/country/2020/country-2020-01-31.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_8082c23b-a50d-492e-a26c-fb24eaa19254" xlink:to="loc_country_US_216bc4d5-bec8-4061-ae3b-12acdd88718d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_NonUsExcludingJapanMember_a28111fe-59ba-4551-9cc1-479432db09ef" xlink:href="amgn-20201231.xsd#amgn_NonUsExcludingJapanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_8082c23b-a50d-492e-a26c-fb24eaa19254" xlink:to="loc_amgn_NonUsExcludingJapanMember_a28111fe-59ba-4551-9cc1-479432db09ef" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/CollaborationsBeiGeneDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#CollaborationsBeiGeneDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/CollaborationsBeiGeneDetails" xlink:type="extended" id="i9ade6cdb14714531a010cd2fdb3eaa0d_CollaborationsBeiGeneDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_6886c88e-d1c9-44a2-9b3e-bc0fab192cb4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersCostsIncurredGross_b947b285-41d9-4503-9b29-7f4caa9da17c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersCostsIncurredGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_6886c88e-d1c9-44a2-9b3e-bc0fab192cb4" xlink:to="loc_us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersCostsIncurredGross_b947b285-41d9-4503-9b29-7f4caa9da17c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RecoveryOfDirectCosts_40d66528-b527-44d7-a3d2-fae8bfe5ab98" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RecoveryOfDirectCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_6886c88e-d1c9-44a2-9b3e-bc0fab192cb4" xlink:to="loc_us-gaap_RecoveryOfDirectCosts_40d66528-b527-44d7-a3d2-fae8bfe5ab98" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_RecoveryOfDirectCostsReceivable_ce5fb0b6-528e-4029-a85f-06f33058c2da" xlink:href="amgn-20201231.xsd#amgn_RecoveryOfDirectCostsReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_6886c88e-d1c9-44a2-9b3e-bc0fab192cb4" xlink:to="loc_amgn_RecoveryOfDirectCostsReceivable_ce5fb0b6-528e-4029-a85f-06f33058c2da" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_d6254788-23ab-422a-ac83-d259030f2fe8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_6886c88e-d1c9-44a2-9b3e-bc0fab192cb4" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_d6254788-23ab-422a-ac83-d259030f2fe8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentAggregateCost_9204bc4a-7868-43f7-b029-5be544794477" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvestmentAggregateCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_6886c88e-d1c9-44a2-9b3e-bc0fab192cb4" xlink:to="loc_us-gaap_EquityMethodInvestmentAggregateCost_9204bc4a-7868-43f7-b029-5be544794477" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_8ede5a44-cc1c-45ae-8b5d-b46e275a6101" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_6886c88e-d1c9-44a2-9b3e-bc0fab192cb4" xlink:to="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_8ede5a44-cc1c-45ae-8b5d-b46e275a6101" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfArrangementAxis_4d055969-ec92-4dc4-8c50-6f4bdc8d8586" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfArrangementAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_8ede5a44-cc1c-45ae-8b5d-b46e275a6101" xlink:to="loc_us-gaap_TypeOfArrangementAxis_4d055969-ec92-4dc4-8c50-6f4bdc8d8586" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_4d055969-ec92-4dc4-8c50-6f4bdc8d8586_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TypeOfArrangementAxis_4d055969-ec92-4dc4-8c50-6f4bdc8d8586" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_4d055969-ec92-4dc4-8c50-6f4bdc8d8586_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_bbaef52c-d2ad-4c2a-a8c5-e4c6e9bc9a68" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TypeOfArrangementAxis_4d055969-ec92-4dc4-8c50-6f4bdc8d8586" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_bbaef52c-d2ad-4c2a-a8c5-e4c6e9bc9a68" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_BeiGeneMember_e5804253-da47-4bc3-afac-ff9bd02a4219" xlink:href="amgn-20201231.xsd#amgn_BeiGeneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_bbaef52c-d2ad-4c2a-a8c5-e4c6e9bc9a68" xlink:to="loc_amgn_BeiGeneMember_e5804253-da47-4bc3-afac-ff9bd02a4219" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_5d5997f7-a9d6-4d8a-a25d-66d2a5f1b06f" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_8ede5a44-cc1c-45ae-8b5d-b46e275a6101" xlink:to="loc_srt_CounterpartyNameAxis_5d5997f7-a9d6-4d8a-a25d-66d2a5f1b06f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_5d5997f7-a9d6-4d8a-a25d-66d2a5f1b06f_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_5d5997f7-a9d6-4d8a-a25d-66d2a5f1b06f" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_5d5997f7-a9d6-4d8a-a25d-66d2a5f1b06f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_658845d3-670a-4115-a3c3-61cb8470633f" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_5d5997f7-a9d6-4d8a-a25d-66d2a5f1b06f" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_658845d3-670a-4115-a3c3-61cb8470633f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_018e593c-a5fd-4097-a5bf-33eaf3796c91" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_8ede5a44-cc1c-45ae-8b5d-b46e275a6101" xlink:to="loc_srt_ProductOrServiceAxis_018e593c-a5fd-4097-a5bf-33eaf3796c91" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_018e593c-a5fd-4097-a5bf-33eaf3796c91_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_018e593c-a5fd-4097-a5bf-33eaf3796c91" xlink:to="loc_srt_ProductsAndServicesDomain_018e593c-a5fd-4097-a5bf-33eaf3796c91_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_2be1f29a-a324-41de-ba7e-2896f2afa7fd" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_018e593c-a5fd-4097-a5bf-33eaf3796c91" xlink:to="loc_srt_ProductsAndServicesDomain_2be1f29a-a324-41de-ba7e-2896f2afa7fd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_6d70f2af-10c5-4725-99c4-221e43c88f4a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_8ede5a44-cc1c-45ae-8b5d-b46e275a6101" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_6d70f2af-10c5-4725-99c4-221e43c88f4a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_6d70f2af-10c5-4725-99c4-221e43c88f4a_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_6d70f2af-10c5-4725-99c4-221e43c88f4a" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_6d70f2af-10c5-4725-99c4-221e43c88f4a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_5e293d1b-8d4a-4bdc-8ec8-ace44fbc30a2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_6d70f2af-10c5-4725-99c4-221e43c88f4a" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_5e293d1b-8d4a-4bdc-8ec8-ace44fbc30a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseMember_85ca80f7-f816-4ff9-afd4-ee91093076db" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ResearchAndDevelopmentExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_5e293d1b-8d4a-4bdc-8ec8-ace44fbc30a2" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseMember_85ca80f7-f816-4ff9-afd4-ee91093076db" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_07bd719c-2fe7-417c-9ce1-39b70d236be2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_8ede5a44-cc1c-45ae-8b5d-b46e275a6101" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_07bd719c-2fe7-417c-9ce1-39b70d236be2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_07bd719c-2fe7-417c-9ce1-39b70d236be2_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_07bd719c-2fe7-417c-9ce1-39b70d236be2" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_07bd719c-2fe7-417c-9ce1-39b70d236be2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_da4ab916-dc5c-47be-b201-1bd0c7bbed78" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_07bd719c-2fe7-417c-9ce1-39b70d236be2" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_da4ab916-dc5c-47be-b201-1bd0c7bbed78" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCurrentAssetsMember_d3ef7f00-9531-4cca-9759-ae1c5d5407d3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherCurrentAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_da4ab916-dc5c-47be-b201-1bd0c7bbed78" xlink:to="loc_us-gaap_OtherCurrentAssetsMember_d3ef7f00-9531-4cca-9759-ae1c5d5407d3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_4225364e-e747-4b5f-9c06-71b5e3ba8b80" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_8ede5a44-cc1c-45ae-8b5d-b46e275a6101" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_4225364e-e747-4b5f-9c06-71b5e3ba8b80" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_4225364e-e747-4b5f-9c06-71b5e3ba8b80_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_4225364e-e747-4b5f-9c06-71b5e3ba8b80" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_4225364e-e747-4b5f-9c06-71b5e3ba8b80_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_e34888e2-1815-41e5-9183-47dd1f791938" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_4225364e-e747-4b5f-9c06-71b5e3ba8b80" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_e34888e2-1815-41e5-9183-47dd1f791938" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_BeiGeneMember_059cc2d6-11e3-45cc-88bd-f39f2a517898" xlink:href="amgn-20201231.xsd#amgn_BeiGeneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_e34888e2-1815-41e5-9183-47dd1f791938" xlink:to="loc_amgn_BeiGeneMember_059cc2d6-11e3-45cc-88bd-f39f2a517898" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/Investments" xlink:type="simple" xlink:href="amgn-20201231.xsd#Investments"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/Investments" xlink:type="extended" id="iabc4f02856b84d64b503dba43d31351f_Investments"/>
  <link:roleRef roleURI="http://www.amgen.com/role/InvestmentsTables" xlink:type="simple" xlink:href="amgn-20201231.xsd#InvestmentsTables"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/InvestmentsTables" xlink:type="extended" id="iff01ee13b02e41eca412e4a2c002d72e_InvestmentsTables"/>
  <link:roleRef roleURI="http://www.amgen.com/role/InvestmentsScheduleDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#InvestmentsScheduleDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/InvestmentsScheduleDetails" xlink:type="extended" id="i0c77a49c60a64fbe8c03fbba8b62e5d5_InvestmentsScheduleDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_f6c6a1a6-3077-41f3-80f8-4828e2b9d7b0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesAbstract_0fcd32aa-bba3-4bfe-8ec9-b9e95b2534a9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_f6c6a1a6-3077-41f3-80f8-4828e2b9d7b0" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesAbstract_0fcd32aa-bba3-4bfe-8ec9-b9e95b2534a9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_febf10dc-790a-4766-a176-b2eb274ecef7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_0fcd32aa-bba3-4bfe-8ec9-b9e95b2534a9" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_febf10dc-790a-4766-a176-b2eb274ecef7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_23c50fb4-8cd9-4b1b-9758-8e6e2f5a0ee1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_0fcd32aa-bba3-4bfe-8ec9-b9e95b2534a9" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_23c50fb4-8cd9-4b1b-9758-8e6e2f5a0ee1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_d17e9d7a-48d4-419c-87c0-b37f11558c51" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_0fcd32aa-bba3-4bfe-8ec9-b9e95b2534a9" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_d17e9d7a-48d4-419c-87c0-b37f11558c51" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_5160b5b1-fd17-4f34-8ce6-8a1af87ae0f6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_0fcd32aa-bba3-4bfe-8ec9-b9e95b2534a9" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_5160b5b1-fd17-4f34-8ce6-8a1af87ae0f6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_73a56420-22bb-47c9-8d6e-d51f675855d6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_f6c6a1a6-3077-41f3-80f8-4828e2b9d7b0" xlink:to="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_73a56420-22bb-47c9-8d6e-d51f675855d6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_44006225-b1c6-4501-91bc-ee3a2f2f7fb4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_73a56420-22bb-47c9-8d6e-d51f675855d6" xlink:to="loc_us-gaap_FinancialInstrumentAxis_44006225-b1c6-4501-91bc-ee3a2f2f7fb4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_44006225-b1c6-4501-91bc-ee3a2f2f7fb4_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_44006225-b1c6-4501-91bc-ee3a2f2f7fb4" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_44006225-b1c6-4501-91bc-ee3a2f2f7fb4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_90afe074-11e5-41bc-87db-0448752bf828" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_44006225-b1c6-4501-91bc-ee3a2f2f7fb4" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_90afe074-11e5-41bc-87db-0448752bf828" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_d1f7e154-e982-46d0-bf08-c6840c87b90c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_90afe074-11e5-41bc-87db-0448752bf828" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_d1f7e154-e982-46d0-bf08-c6840c87b90c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasuryBillSecuritiesMember_60f599d2-a0a8-4605-b7fb-6c5c237fc7fa" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_USTreasuryBillSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_90afe074-11e5-41bc-87db-0448752bf828" xlink:to="loc_us-gaap_USTreasuryBillSecuritiesMember_60f599d2-a0a8-4605-b7fb-6c5c237fc7fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CorporateDebtSecuritiesFinancialMember_5f13d6eb-9aac-4e95-bb20-4eaa089ab4d3" xlink:href="amgn-20201231.xsd#amgn_CorporateDebtSecuritiesFinancialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_90afe074-11e5-41bc-87db-0448752bf828" xlink:to="loc_amgn_CorporateDebtSecuritiesFinancialMember_5f13d6eb-9aac-4e95-bb20-4eaa089ab4d3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CorporateDebtSecuritiesIndustrialMember_11ec3c7b-cb48-4d59-ab65-798dbb169502" xlink:href="amgn-20201231.xsd#amgn_CorporateDebtSecuritiesIndustrialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_90afe074-11e5-41bc-87db-0448752bf828" xlink:to="loc_amgn_CorporateDebtSecuritiesIndustrialMember_11ec3c7b-cb48-4d59-ab65-798dbb169502" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CorporateDebtSecuritiesOtherMember_ecd050f0-fe38-4c34-86b9-4590f8cafd3d" xlink:href="amgn-20201231.xsd#amgn_CorporateDebtSecuritiesOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_90afe074-11e5-41bc-87db-0448752bf828" xlink:to="loc_amgn_CorporateDebtSecuritiesOtherMember_ecd050f0-fe38-4c34-86b9-4590f8cafd3d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_5c5223d1-387a-464b-8997-2cd5d06d4263" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ResidentialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_90afe074-11e5-41bc-87db-0448752bf828" xlink:to="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_5c5223d1-387a-464b-8997-2cd5d06d4263" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_f2c5cd19-95dd-4407-9b06-3a9fb32e465a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_90afe074-11e5-41bc-87db-0448752bf828" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_f2c5cd19-95dd-4407-9b06-3a9fb32e465a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsMember_43afbbf8-f779-49ad-a82d-e0d54e7f456c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MoneyMarketFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_90afe074-11e5-41bc-87db-0448752bf828" xlink:to="loc_us-gaap_MoneyMarketFundsMember_43afbbf8-f779-49ad-a82d-e0d54e7f456c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_OtherShortTermInterestBearingSecuritiesMember_a4b1ec79-e567-4875-b6f0-f77bdb845a88" xlink:href="amgn-20201231.xsd#amgn_OtherShortTermInterestBearingSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_90afe074-11e5-41bc-87db-0448752bf828" xlink:to="loc_amgn_OtherShortTermInterestBearingSecuritiesMember_a4b1ec79-e567-4875-b6f0-f77bdb845a88" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/InvestmentsFairValuesbyClassificationDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#InvestmentsFairValuesbyClassificationDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/InvestmentsFairValuesbyClassificationDetails" xlink:type="extended" id="i55bce9aa31da4958b46c5e44b2e5f8c6_InvestmentsFairValuesbyClassificationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_e40fa892-ff8f-4845-8bb0-64bd47b16177" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FairValuesOfAvailableForSaleInvestmentsByClassificationInConsolidatedBalanceSheetsAbstract_0b4d4495-467f-4db6-a18e-8a89b7b17114" xlink:href="amgn-20201231.xsd#amgn_FairValuesOfAvailableForSaleInvestmentsByClassificationInConsolidatedBalanceSheetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_e40fa892-ff8f-4845-8bb0-64bd47b16177" xlink:to="loc_amgn_FairValuesOfAvailableForSaleInvestmentsByClassificationInConsolidatedBalanceSheetsAbstract_0b4d4495-467f-4db6-a18e-8a89b7b17114" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_1e65d2ae-2f01-49df-aef6-1286b2f6f961" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amgn_FairValuesOfAvailableForSaleInvestmentsByClassificationInConsolidatedBalanceSheetsAbstract_0b4d4495-467f-4db6-a18e-8a89b7b17114" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_1e65d2ae-2f01-49df-aef6-1286b2f6f961" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent_4352a495-0423-453d-89c5-215505c2b1a1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amgn_FairValuesOfAvailableForSaleInvestmentsByClassificationInConsolidatedBalanceSheetsAbstract_0b4d4495-467f-4db6-a18e-8a89b7b17114" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent_4352a495-0423-453d-89c5-215505c2b1a1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_6cd9c3cd-0b56-4e1c-8e9c-2ee5e3653bae" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amgn_FairValuesOfAvailableForSaleInvestmentsByClassificationInConsolidatedBalanceSheetsAbstract_0b4d4495-467f-4db6-a18e-8a89b7b17114" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_6cd9c3cd-0b56-4e1c-8e9c-2ee5e3653bae" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_c7cfb1f4-aac6-41de-8e26-b2a04c9d4b68" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_e40fa892-ff8f-4845-8bb0-64bd47b16177" xlink:to="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_c7cfb1f4-aac6-41de-8e26-b2a04c9d4b68" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_b894d7f1-8c6f-405c-b3d7-0192f77898c7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_c7cfb1f4-aac6-41de-8e26-b2a04c9d4b68" xlink:to="loc_us-gaap_FinancialInstrumentAxis_b894d7f1-8c6f-405c-b3d7-0192f77898c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b894d7f1-8c6f-405c-b3d7-0192f77898c7_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_b894d7f1-8c6f-405c-b3d7-0192f77898c7" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b894d7f1-8c6f-405c-b3d7-0192f77898c7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_9bd2987a-04f1-4893-856a-f985c85666c2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_b894d7f1-8c6f-405c-b3d7-0192f77898c7" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_9bd2987a-04f1-4893-856a-f985c85666c2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_AvailableForSalesInvestmentsMember_e8b2003a-23c9-4d43-8e60-630f0b10caea" xlink:href="amgn-20201231.xsd#amgn_AvailableForSalesInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_9bd2987a-04f1-4893-856a-f985c85666c2" xlink:to="loc_amgn_AvailableForSalesInvestmentsMember_e8b2003a-23c9-4d43-8e60-630f0b10caea" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/InvestmentsAvailableforsaleDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#InvestmentsAvailableforsaleDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/InvestmentsAvailableforsaleDetails" xlink:type="extended" id="i77356938f9cd44eba9abed4e7c1cb840_InvestmentsAvailableforsaleDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/InvestmentsFairValuesbyContractualMaturityDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#InvestmentsFairValuesbyContractualMaturityDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/InvestmentsFairValuesbyContractualMaturityDetails" xlink:type="extended" id="ia3b40aa3ef5b43be8857cf26712a4f5d_InvestmentsFairValuesbyContractualMaturityDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/InvestmentsEquitySecuritiesDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#InvestmentsEquitySecuritiesDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/InvestmentsEquitySecuritiesDetails" xlink:type="extended" id="i80d1f4edc8a043e8a8bc2e963d88de8b_InvestmentsEquitySecuritiesDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/InvestmentsLimitedPartnershipInvestmentsDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#InvestmentsLimitedPartnershipInvestmentsDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/InvestmentsLimitedPartnershipInvestmentsDetails" xlink:type="extended" id="i6615e9f633ec4ddb8b238fda78d9c4ea_InvestmentsLimitedPartnershipInvestmentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_43cf2d3c-66d1-41fb-903d-deff80bcfc44" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AlternativeInvestment_d333bf7a-4387-4c8d-877f-d60a6a3022ad" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AlternativeInvestment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_43cf2d3c-66d1-41fb-903d-deff80bcfc44" xlink:to="loc_us-gaap_AlternativeInvestment_d333bf7a-4387-4c8d-877f-d60a6a3022ad" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_AlternativeInvestmentNetGainLoss_ff259424-9111-47dd-a41c-c04b13b5ad40" xlink:href="amgn-20201231.xsd#amgn_AlternativeInvestmentNetGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_43cf2d3c-66d1-41fb-903d-deff80bcfc44" xlink:to="loc_amgn_AlternativeInvestmentNetGainLoss_ff259424-9111-47dd-a41c-c04b13b5ad40" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_f8ef1113-745f-4ab9-be11-49e1f41bd5e2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_43cf2d3c-66d1-41fb-903d-deff80bcfc44" xlink:to="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_f8ef1113-745f-4ab9-be11-49e1f41bd5e2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeAxis_f327ce10-d715-480b-9705-9b45505f5ecf" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_f8ef1113-745f-4ab9-be11-49e1f41bd5e2" xlink:to="loc_us-gaap_InvestmentTypeAxis_f327ce10-d715-480b-9705-9b45505f5ecf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_f327ce10-d715-480b-9705-9b45505f5ecf_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_f327ce10-d715-480b-9705-9b45505f5ecf" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_f327ce10-d715-480b-9705-9b45505f5ecf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_028dc097-28e4-4e3b-9ac5-5cca6b558cde" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_f327ce10-d715-480b-9705-9b45505f5ecf" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_028dc097-28e4-4e3b-9ac5-5cca6b558cde" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_PartnershipInterestMember_98a241d8-a77c-4473-bb47-8c83a2225f61" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_PartnershipInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_028dc097-28e4-4e3b-9ac5-5cca6b558cde" xlink:to="loc_srt_PartnershipInterestMember_98a241d8-a77c-4473-bb47-8c83a2225f61" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_086f9e3f-61f3-45db-90cf-b05d4003b9d5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_f8ef1113-745f-4ab9-be11-49e1f41bd5e2" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_086f9e3f-61f3-45db-90cf-b05d4003b9d5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_086f9e3f-61f3-45db-90cf-b05d4003b9d5_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_086f9e3f-61f3-45db-90cf-b05d4003b9d5" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_086f9e3f-61f3-45db-90cf-b05d4003b9d5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_ce015675-db79-45a6-94fb-615c3d2ce934" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_086f9e3f-61f3-45db-90cf-b05d4003b9d5" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_ce015675-db79-45a6-94fb-615c3d2ce934" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember_dc946008-74df-45e6-bf93-aaac70c305c5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_ce015675-db79-45a6-94fb-615c3d2ce934" xlink:to="loc_us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember_dc946008-74df-45e6-bf93-aaac70c305c5" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/InvestmentsBeiGeneDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#InvestmentsBeiGeneDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/InvestmentsBeiGeneDetails" xlink:type="extended" id="ib44540ff4415432c8c5079ec912f1196_InvestmentsBeiGeneDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_3f468411-b0b8-478f-b3fe-5fa90fe57bee" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_ef16c02c-03fc-479b-9143-919ea1a371ba" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_3f468411-b0b8-478f-b3fe-5fa90fe57bee" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_ef16c02c-03fc-479b-9143-919ea1a371ba" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentAggregateCost_9b749749-11bc-4925-a375-79fca290ead3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvestmentAggregateCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_3f468411-b0b8-478f-b3fe-5fa90fe57bee" xlink:to="loc_us-gaap_EquityMethodInvestmentAggregateCost_9b749749-11bc-4925-a375-79fca290ead3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentQuotedMarketValue_793e0d8d-09b2-4e45-8df0-669fff00e8cd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvestmentQuotedMarketValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_3f468411-b0b8-478f-b3fe-5fa90fe57bee" xlink:to="loc_us-gaap_EquityMethodInvestmentQuotedMarketValue_793e0d8d-09b2-4e45-8df0-669fff00e8cd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity_860d2d7a-ddbd-447e-a7d9-ab05d8ad57ae" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_3f468411-b0b8-478f-b3fe-5fa90fe57bee" xlink:to="loc_us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity_860d2d7a-ddbd-447e-a7d9-ab05d8ad57ae" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_1c94dd54-4e15-405a-8e0d-f3e92dce194a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_3f468411-b0b8-478f-b3fe-5fa90fe57bee" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_1c94dd54-4e15-405a-8e0d-f3e92dce194a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_EquityMethodInvestmentChangeInCarryingValue_8f19655e-cd75-4e69-80ed-d82db554c2a0" xlink:href="amgn-20201231.xsd#amgn_EquityMethodInvestmentChangeInCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_3f468411-b0b8-478f-b3fe-5fa90fe57bee" xlink:to="loc_amgn_EquityMethodInvestmentChangeInCarryingValue_8f19655e-cd75-4e69-80ed-d82db554c2a0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_EquityMethodInvestmentChangeInCarryingValueOther_49b709ad-06ab-44e6-94ca-5a21c4314713" xlink:href="amgn-20201231.xsd#amgn_EquityMethodInvestmentChangeInCarryingValueOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_3f468411-b0b8-478f-b3fe-5fa90fe57bee" xlink:to="loc_amgn_EquityMethodInvestmentChangeInCarryingValueOther_49b709ad-06ab-44e6-94ca-5a21c4314713" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_0de030a2-c9e9-46b0-8ebb-e23f9ac8076e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_3f468411-b0b8-478f-b3fe-5fa90fe57bee" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_0de030a2-c9e9-46b0-8ebb-e23f9ac8076e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_EquityMethodInvestmentAmortizationOfDifferenceBetweenCarryingAmountAndUnderlyingEquity_20e97515-3bc0-4ce2-9157-727c15163541" xlink:href="amgn-20201231.xsd#amgn_EquityMethodInvestmentAmortizationOfDifferenceBetweenCarryingAmountAndUnderlyingEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_3f468411-b0b8-478f-b3fe-5fa90fe57bee" xlink:to="loc_amgn_EquityMethodInvestmentAmortizationOfDifferenceBetweenCarryingAmountAndUnderlyingEquity_20e97515-3bc0-4ce2-9157-727c15163541" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments_e98ef61b-3e43-4b91-8e37-2ca96e8e6669" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_3f468411-b0b8-478f-b3fe-5fa90fe57bee" xlink:to="loc_us-gaap_EquityMethodInvestments_e98ef61b-3e43-4b91-8e37-2ca96e8e6669" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_b9360b7f-28bf-43e2-9eb7-d419fc2521d7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_3f468411-b0b8-478f-b3fe-5fa90fe57bee" xlink:to="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_b9360b7f-28bf-43e2-9eb7-d419fc2521d7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_d2bde0bb-85cc-4ec3-a128-5dac1c198b30" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_b9360b7f-28bf-43e2-9eb7-d419fc2521d7" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_d2bde0bb-85cc-4ec3-a128-5dac1c198b30" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_d2bde0bb-85cc-4ec3-a128-5dac1c198b30_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_d2bde0bb-85cc-4ec3-a128-5dac1c198b30" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_d2bde0bb-85cc-4ec3-a128-5dac1c198b30_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_e1e99871-7c0b-4ef9-9a5d-a67f6f04e731" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_d2bde0bb-85cc-4ec3-a128-5dac1c198b30" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_e1e99871-7c0b-4ef9-9a5d-a67f6f04e731" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_BeiGeneMember_5b3e0375-9279-4285-9380-b620314bd715" xlink:href="amgn-20201231.xsd#amgn_BeiGeneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_e1e99871-7c0b-4ef9-9a5d-a67f6f04e731" xlink:to="loc_amgn_BeiGeneMember_5b3e0375-9279-4285-9380-b620314bd715" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_2255c03e-b8e3-4628-861d-a18efce0a9bb" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_b9360b7f-28bf-43e2-9eb7-d419fc2521d7" xlink:to="loc_srt_RangeAxis_2255c03e-b8e3-4628-861d-a18efce0a9bb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_2255c03e-b8e3-4628-861d-a18efce0a9bb_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_2255c03e-b8e3-4628-861d-a18efce0a9bb" xlink:to="loc_srt_RangeMember_2255c03e-b8e3-4628-861d-a18efce0a9bb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_9688dfd0-84ad-458e-9ab1-525ce2cad1e0" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_2255c03e-b8e3-4628-861d-a18efce0a9bb" xlink:to="loc_srt_RangeMember_9688dfd0-84ad-458e-9ab1-525ce2cad1e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_6d58123f-322c-4f85-9c52-f2ac00fb2298" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_9688dfd0-84ad-458e-9ab1-525ce2cad1e0" xlink:to="loc_srt_MinimumMember_6d58123f-322c-4f85-9c52-f2ac00fb2298" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_ab7d1f7f-9442-46c8-994f-e7fd45ad3890" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_9688dfd0-84ad-458e-9ab1-525ce2cad1e0" xlink:to="loc_srt_MaximumMember_ab7d1f7f-9442-46c8-994f-e7fd45ad3890" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/Inventories" xlink:type="simple" xlink:href="amgn-20201231.xsd#Inventories"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/Inventories" xlink:type="extended" id="i8b05311e0d304d23943c455e8c484a5b_Inventories"/>
  <link:roleRef roleURI="http://www.amgen.com/role/InventoriesTables" xlink:type="simple" xlink:href="amgn-20201231.xsd#InventoriesTables"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/InventoriesTables" xlink:type="extended" id="ieb08815d52b14809b9745efd2b9b2f45_InventoriesTables"/>
  <link:roleRef roleURI="http://www.amgen.com/role/InventoriesDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#InventoriesDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/InventoriesDetails" xlink:type="extended" id="i156a58e84a1540bdba1cfe739666d3a7_InventoriesDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/Propertyplantandequipment" xlink:type="simple" xlink:href="amgn-20201231.xsd#Propertyplantandequipment"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/Propertyplantandequipment" xlink:type="extended" id="ie772cfa98d7e41aaa31a115e489bfb46_Propertyplantandequipment"/>
  <link:roleRef roleURI="http://www.amgen.com/role/PropertyplantandequipmentTables" xlink:type="simple" xlink:href="amgn-20201231.xsd#PropertyplantandequipmentTables"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/PropertyplantandequipmentTables" xlink:type="extended" id="i4b736e63295944b7b775110dc4c8811c_PropertyplantandequipmentTables"/>
  <link:roleRef roleURI="http://www.amgen.com/role/PropertyplantandequipmentScheduleDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#PropertyplantandequipmentScheduleDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/PropertyplantandequipmentScheduleDetails" xlink:type="extended" id="ibfae6855c3c042a28dc4445a07833232_PropertyplantandequipmentScheduleDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3e378b35-347b-44a0-a2e6-d84a2659a494" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_14767723-5b4f-4d14-a837-5936e50f4ed6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3e378b35-347b-44a0-a2e6-d84a2659a494" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_14767723-5b4f-4d14-a837-5936e50f4ed6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Land_edfacf05-0b87-4c0f-a826-c6768fdc3f36" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Land"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3e378b35-347b-44a0-a2e6-d84a2659a494" xlink:to="loc_us-gaap_Land_edfacf05-0b87-4c0f-a826-c6768fdc3f36" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingsAndImprovementsGross_a8b3658b-b842-4de4-b788-cc9ea4570169" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BuildingsAndImprovementsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3e378b35-347b-44a0-a2e6-d84a2659a494" xlink:to="loc_us-gaap_BuildingsAndImprovementsGross_a8b3658b-b842-4de4-b788-cc9ea4570169" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MachineryAndEquipmentGross_6d907f36-8ea4-4bef-8b97-d487c7b0a76b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MachineryAndEquipmentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3e378b35-347b-44a0-a2e6-d84a2659a494" xlink:to="loc_us-gaap_MachineryAndEquipmentGross_6d907f36-8ea4-4bef-8b97-d487c7b0a76b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_LaboratoryEquipment_b3979e00-e4d5-4916-a188-22e6ccd3e2db" xlink:href="amgn-20201231.xsd#amgn_LaboratoryEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3e378b35-347b-44a0-a2e6-d84a2659a494" xlink:to="loc_amgn_LaboratoryEquipment_b3979e00-e4d5-4916-a188-22e6ccd3e2db" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FixedEquipment_8fe80ede-f687-42f6-8b22-5ee264357024" xlink:href="amgn-20201231.xsd#amgn_FixedEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3e378b35-347b-44a0-a2e6-d84a2659a494" xlink:to="loc_amgn_FixedEquipment_8fe80ede-f687-42f6-8b22-5ee264357024" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedComputerSoftwareGross_be78e76c-3b3c-452c-b01a-a062046e4f83" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalizedComputerSoftwareGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3e378b35-347b-44a0-a2e6-d84a2659a494" xlink:to="loc_us-gaap_CapitalizedComputerSoftwareGross_be78e76c-3b3c-452c-b01a-a062046e4f83" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentOther_61db1c81-e138-4ba3-91f6-570543f03ba6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3e378b35-347b-44a0-a2e6-d84a2659a494" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentOther_61db1c81-e138-4ba3-91f6-570543f03ba6" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressGross_a0738437-08b8-4049-afe6-b7922ab1abc5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConstructionInProgressGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3e378b35-347b-44a0-a2e6-d84a2659a494" xlink:to="loc_us-gaap_ConstructionInProgressGross_a0738437-08b8-4049-afe6-b7922ab1abc5" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_44f927fe-9f1f-4ba5-a65c-3e475d129e35" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3e378b35-347b-44a0-a2e6-d84a2659a494" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_44f927fe-9f1f-4ba5-a65c-3e475d129e35" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_a081d631-c803-4325-9c6a-a96765bb7ef9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3e378b35-347b-44a0-a2e6-d84a2659a494" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_a081d631-c803-4325-9c6a-a96765bb7ef9" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_86707a22-4fcd-44ac-b735-6fc789f38be0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3e378b35-347b-44a0-a2e6-d84a2659a494" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_86707a22-4fcd-44ac-b735-6fc789f38be0" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_c9eb0dbb-b27f-4e96-8d31-cde702878d31" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Depreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3e378b35-347b-44a0-a2e6-d84a2659a494" xlink:to="loc_us-gaap_Depreciation_c9eb0dbb-b27f-4e96-8d31-cde702878d31" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_41c6c8e7-bc11-4ba6-a09d-cb91f609a154" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3e378b35-347b-44a0-a2e6-d84a2659a494" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_41c6c8e7-bc11-4ba6-a09d-cb91f609a154" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_39eab571-604e-48d5-97a5-24ca4518e2df" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_41c6c8e7-bc11-4ba6-a09d-cb91f609a154" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_39eab571-604e-48d5-97a5-24ca4518e2df" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_39eab571-604e-48d5-97a5-24ca4518e2df_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_39eab571-604e-48d5-97a5-24ca4518e2df" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_39eab571-604e-48d5-97a5-24ca4518e2df_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_67b34ceb-001d-4dfc-8637-ec122d3ed6f7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_39eab571-604e-48d5-97a5-24ca4518e2df" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_67b34ceb-001d-4dfc-8637-ec122d3ed6f7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_a1f37396-9506-462d-a743-45f60e29c37b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BuildingAndBuildingImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_67b34ceb-001d-4dfc-8637-ec122d3ed6f7" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_a1f37396-9506-462d-a743-45f60e29c37b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ManufacturingEquipmentMember_093853c5-385e-45a7-b01e-2d5abc68b9ba" xlink:href="amgn-20201231.xsd#amgn_ManufacturingEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_67b34ceb-001d-4dfc-8637-ec122d3ed6f7" xlink:to="loc_amgn_ManufacturingEquipmentMember_093853c5-385e-45a7-b01e-2d5abc68b9ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_LaboratoryEquipmentMember_af4984dd-42db-4faf-8609-a205db26ebba" xlink:href="amgn-20201231.xsd#amgn_LaboratoryEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_67b34ceb-001d-4dfc-8637-ec122d3ed6f7" xlink:to="loc_amgn_LaboratoryEquipmentMember_af4984dd-42db-4faf-8609-a205db26ebba" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FixedEquipmentMember_4d72c92c-fae3-4f71-bb75-a52bcc56054f" xlink:href="amgn-20201231.xsd#amgn_FixedEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_67b34ceb-001d-4dfc-8637-ec122d3ed6f7" xlink:to="loc_amgn_FixedEquipmentMember_4d72c92c-fae3-4f71-bb75-a52bcc56054f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SoftwareAndSoftwareDevelopmentCostsMember_be21adf9-a1a6-4819-a1d6-649d24a0a86f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SoftwareAndSoftwareDevelopmentCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_67b34ceb-001d-4dfc-8637-ec122d3ed6f7" xlink:to="loc_us-gaap_SoftwareAndSoftwareDevelopmentCostsMember_be21adf9-a1a6-4819-a1d6-649d24a0a86f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentOtherTypesMember_a3acbef9-9e74-45a7-8e8f-ab92400ced85" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentOtherTypesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_67b34ceb-001d-4dfc-8637-ec122d3ed6f7" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentOtherTypesMember_a3acbef9-9e74-45a7-8e8f-ab92400ced85" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_37115a26-2dea-4959-9c41-a0185c457d17" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_41c6c8e7-bc11-4ba6-a09d-cb91f609a154" xlink:to="loc_srt_RangeAxis_37115a26-2dea-4959-9c41-a0185c457d17" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_37115a26-2dea-4959-9c41-a0185c457d17_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_37115a26-2dea-4959-9c41-a0185c457d17" xlink:to="loc_srt_RangeMember_37115a26-2dea-4959-9c41-a0185c457d17_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_073dc7d4-5066-469c-ab10-158ad4a32beb" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_37115a26-2dea-4959-9c41-a0185c457d17" xlink:to="loc_srt_RangeMember_073dc7d4-5066-469c-ab10-158ad4a32beb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_9b7e3a51-1bd7-4661-a07f-0c90ee72870d" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_073dc7d4-5066-469c-ab10-158ad4a32beb" xlink:to="loc_srt_MinimumMember_9b7e3a51-1bd7-4661-a07f-0c90ee72870d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_4a1c9a56-b9c5-4b76-a3e7-3f5b57acfd48" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_073dc7d4-5066-469c-ab10-158ad4a32beb" xlink:to="loc_srt_MaximumMember_4a1c9a56-b9c5-4b76-a3e7-3f5b57acfd48" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/PropertyplantandequipmentGeographicInformationDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#PropertyplantandequipmentGeographicInformationDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/PropertyplantandequipmentGeographicInformationDetails" xlink:type="extended" id="i7065c45cd4e94d4d98bc3288aa989498_PropertyplantandequipmentGeographicInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_ffffe148-b26b-4ad6-86ec-39863377f344" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_ca11ab24-9d22-4471-a9e7-00095a3f0a76" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_ffffe148-b26b-4ad6-86ec-39863377f344" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_ca11ab24-9d22-4471-a9e7-00095a3f0a76" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_3ecbd06f-36b6-441c-87b1-c27316c6ffce" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_ffffe148-b26b-4ad6-86ec-39863377f344" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_3ecbd06f-36b6-441c-87b1-c27316c6ffce" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_ddc619a8-3f4d-4641-8d73-3e416c142fed" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_3ecbd06f-36b6-441c-87b1-c27316c6ffce" xlink:to="loc_srt_StatementGeographicalAxis_ddc619a8-3f4d-4641-8d73-3e416c142fed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_ddc619a8-3f4d-4641-8d73-3e416c142fed_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_ddc619a8-3f4d-4641-8d73-3e416c142fed" xlink:to="loc_srt_SegmentGeographicalDomain_ddc619a8-3f4d-4641-8d73-3e416c142fed_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_e341f5e0-181a-4088-b6ec-86ae6868e458" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_ddc619a8-3f4d-4641-8d73-3e416c142fed" xlink:to="loc_srt_SegmentGeographicalDomain_e341f5e0-181a-4088-b6ec-86ae6868e458" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_cf761a2c-8ddb-42d0-8018-0c88f3a60259" xlink:href="https://xbrl.sec.gov/country/2020/country-2020-01-31.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_e341f5e0-181a-4088-b6ec-86ae6868e458" xlink:to="loc_country_US_cf761a2c-8ddb-42d0-8018-0c88f3a60259" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_PR_7c3c4d11-4eb4-4cb6-b295-50694361a57f" xlink:href="https://xbrl.sec.gov/country/2020/country-2020-01-31.xsd#country_PR"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_e341f5e0-181a-4088-b6ec-86ae6868e458" xlink:to="loc_country_PR_7c3c4d11-4eb4-4cb6-b295-50694361a57f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_RestOfWorldMember_7b024ac1-7583-4bd5-b68a-fdb026cfeb3f" xlink:href="amgn-20201231.xsd#amgn_RestOfWorldMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_e341f5e0-181a-4088-b6ec-86ae6868e458" xlink:to="loc_amgn_RestOfWorldMember_7b024ac1-7583-4bd5-b68a-fdb026cfeb3f" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/Goodwillandintangibleassets" xlink:type="simple" xlink:href="amgn-20201231.xsd#Goodwillandintangibleassets"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/Goodwillandintangibleassets" xlink:type="extended" id="i908235ae42104d37a0f1c34873d562c5_Goodwillandintangibleassets"/>
  <link:roleRef roleURI="http://www.amgen.com/role/GoodwillandotherintangibleassetsTables" xlink:type="simple" xlink:href="amgn-20201231.xsd#GoodwillandotherintangibleassetsTables"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/GoodwillandotherintangibleassetsTables" xlink:type="extended" id="i44ad239c9e854daebe91467291e82130_GoodwillandotherintangibleassetsTables"/>
  <link:roleRef roleURI="http://www.amgen.com/role/GoodwillandotherintangibleassetsGoodwillRollForwardDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#GoodwillandotherintangibleassetsGoodwillRollForwardDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/GoodwillandotherintangibleassetsGoodwillRollForwardDetails" xlink:type="extended" id="i27461f0a7c87467a848393d99d3d1f53_GoodwillandotherintangibleassetsGoodwillRollForwardDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/GoodwillandotherintangibleassetsIdentifiableIntangibleAssetsDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#GoodwillandotherintangibleassetsIdentifiableIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/GoodwillandotherintangibleassetsIdentifiableIntangibleAssetsDetails" xlink:type="extended" id="ic16e4223a9074942b094657ed1645234_GoodwillandotherintangibleassetsIdentifiableIntangibleAssetsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_0510ac17-6d58-469c-81e2-24ed847ff387" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_a1b1ab3e-6168-47de-afaa-ca07d35ef622" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNetAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_0510ac17-6d58-469c-81e2-24ed847ff387" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_a1b1ab3e-6168-47de-afaa-ca07d35ef622" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_6b631fd9-e047-4146-8d49-30f25d63e31f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_a1b1ab3e-6168-47de-afaa-ca07d35ef622" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_6b631fd9-e047-4146-8d49-30f25d63e31f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_fc7214c7-5fc9-4e60-a835-4f389db0efdc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_a1b1ab3e-6168-47de-afaa-ca07d35ef622" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_fc7214c7-5fc9-4e60-a835-4f389db0efdc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_2bb63774-26bf-4030-b103-1a641b6615ab" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_a1b1ab3e-6168-47de-afaa-ca07d35ef622" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_2bb63774-26bf-4030-b103-1a641b6615ab" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwillAbstract_72d6beb5-538a-4db3-8dff-799578dc55d4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwillAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_0510ac17-6d58-469c-81e2-24ed847ff387" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwillAbstract_72d6beb5-538a-4db3-8dff-799578dc55d4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_11b9b9e6-2c05-4505-9932-15e73c4f9fe4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IntangibleAssetsNetExcludingGoodwillAbstract_72d6beb5-538a-4db3-8dff-799578dc55d4" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_11b9b9e6-2c05-4505-9932-15e73c4f9fe4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_IdentifiableIntangibleAssetsGross_98acdcf5-6598-4102-8786-118138cad4a8" xlink:href="amgn-20201231.xsd#amgn_IdentifiableIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_0510ac17-6d58-469c-81e2-24ed847ff387" xlink:to="loc_amgn_IdentifiableIntangibleAssetsGross_98acdcf5-6598-4102-8786-118138cad4a8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_IdentifiableIntangibleAssetsAccumulatedAmortization_ca5376f6-1407-4069-abbc-c997953d1ee7" xlink:href="amgn-20201231.xsd#amgn_IdentifiableIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_0510ac17-6d58-469c-81e2-24ed847ff387" xlink:to="loc_amgn_IdentifiableIntangibleAssetsAccumulatedAmortization_ca5376f6-1407-4069-abbc-c997953d1ee7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_6d8d2dac-45a9-4e96-ba34-309872fb5503" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_0510ac17-6d58-469c-81e2-24ed847ff387" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_6d8d2dac-45a9-4e96-ba34-309872fb5503" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_8d6e439a-2a64-4731-b15e-445f1a5858a2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_0510ac17-6d58-469c-81e2-24ed847ff387" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_8d6e439a-2a64-4731-b15e-445f1a5858a2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_665c7464-2bbe-40f1-b8ee-f2209b0706ab" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_8d6e439a-2a64-4731-b15e-445f1a5858a2" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_665c7464-2bbe-40f1-b8ee-f2209b0706ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_665c7464-2bbe-40f1-b8ee-f2209b0706ab_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_665c7464-2bbe-40f1-b8ee-f2209b0706ab" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_665c7464-2bbe-40f1-b8ee-f2209b0706ab_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_0f7d40cd-7aad-4880-a4ce-eac107cc42d5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_665c7464-2bbe-40f1-b8ee-f2209b0706ab" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_0f7d40cd-7aad-4880-a4ce-eac107cc42d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DevelopedTechnologyRightsMember_27936118-01d9-4d1e-bec1-b8cf682b693c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DevelopedTechnologyRightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_0f7d40cd-7aad-4880-a4ce-eac107cc42d5" xlink:to="loc_us-gaap_DevelopedTechnologyRightsMember_27936118-01d9-4d1e-bec1-b8cf682b693c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LicensingAgreementsMember_63871ae6-b9c5-420b-9679-26e76bb502c2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LicensingAgreementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_0f7d40cd-7aad-4880-a4ce-eac107cc42d5" xlink:to="loc_us-gaap_LicensingAgreementsMember_63871ae6-b9c5-420b-9679-26e76bb502c2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MarketingRelatedIntangibleAssetsMember_094c4034-a3cc-4c40-8545-b579b5fc414f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MarketingRelatedIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_0f7d40cd-7aad-4880-a4ce-eac107cc42d5" xlink:to="loc_us-gaap_MarketingRelatedIntangibleAssetsMember_094c4034-a3cc-4c40-8545-b579b5fc414f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_AcquiredResearchAndDevelopmentTechnologyRightsMember_f46070e4-7178-4dc8-8319-6cde52618c74" xlink:href="amgn-20201231.xsd#amgn_AcquiredResearchAndDevelopmentTechnologyRightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_0f7d40cd-7aad-4880-a4ce-eac107cc42d5" xlink:to="loc_amgn_AcquiredResearchAndDevelopmentTechnologyRightsMember_f46070e4-7178-4dc8-8319-6cde52618c74" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_5b24dfd4-087e-49dc-baf4-fe5a977f4532" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_8d6e439a-2a64-4731-b15e-445f1a5858a2" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_5b24dfd4-087e-49dc-baf4-fe5a977f4532" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_5b24dfd4-087e-49dc-baf4-fe5a977f4532_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_5b24dfd4-087e-49dc-baf4-fe5a977f4532" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_5b24dfd4-087e-49dc-baf4-fe5a977f4532_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_01e5b7e2-5f63-4d9e-a101-4e8eeb2bc61a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_5b24dfd4-087e-49dc-baf4-fe5a977f4532" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_01e5b7e2-5f63-4d9e-a101-4e8eeb2bc61a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InProcessResearchAndDevelopmentMember_02eb1a83-422e-4aab-9587-beae7574c961" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InProcessResearchAndDevelopmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_01e5b7e2-5f63-4d9e-a101-4e8eeb2bc61a" xlink:to="loc_us-gaap_InProcessResearchAndDevelopmentMember_02eb1a83-422e-4aab-9587-beae7574c961" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/GoodwillandotherintangibleassetsNarrativeDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#GoodwillandotherintangibleassetsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/GoodwillandotherintangibleassetsNarrativeDetails" xlink:type="extended" id="i8784e59081374d9c88cd1ae99f1bd468_GoodwillandotherintangibleassetsNarrativeDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/Leases" xlink:type="simple" xlink:href="amgn-20201231.xsd#Leases"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/Leases" xlink:type="extended" id="ic0c5a3b49ce04a278160a58e8388cfc2_Leases"/>
  <link:roleRef roleURI="http://www.amgen.com/role/LeasesTables" xlink:type="simple" xlink:href="amgn-20201231.xsd#LeasesTables"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/LeasesTables" xlink:type="extended" id="i2a3834d62e2547aeb5e4bc75bcae4f14_LeasesTables"/>
  <link:roleRef roleURI="http://www.amgen.com/role/LeasesNarrativeDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#LeasesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/LeasesNarrativeDetails" xlink:type="extended" id="i7c69aa32a0864693901b9318418f1ce8_LeasesNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_0ccbf2c0-6146-4c2b-9620-f7647febfe5d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_67804408-368a-48a3-b181-8aa2af989949" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseRenewalTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_0ccbf2c0-6146-4c2b-9620-f7647febfe5d" xlink:to="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_67804408-368a-48a3-b181-8aa2af989949" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_6bfcd98d-a992-4cf7-a1c7-9e6dbedd1a82" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_0ccbf2c0-6146-4c2b-9620-f7647febfe5d" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_6bfcd98d-a992-4cf7-a1c7-9e6dbedd1a82" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_28186cb2-20e1-4a79-a1c2-fbc06f666a06" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_0ccbf2c0-6146-4c2b-9620-f7647febfe5d" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_28186cb2-20e1-4a79-a1c2-fbc06f666a06" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_LesseeOperatingLeaseLeaseNotYetCommencedUndiscountedAmount_14854e15-d879-4c83-9c03-82e480230d9c" xlink:href="amgn-20201231.xsd#amgn_LesseeOperatingLeaseLeaseNotYetCommencedUndiscountedAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_0ccbf2c0-6146-4c2b-9620-f7647febfe5d" xlink:to="loc_amgn_LesseeOperatingLeaseLeaseNotYetCommencedUndiscountedAmount_14854e15-d879-4c83-9c03-82e480230d9c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1_0a197de8-ebb8-4a2e-bbbe-4785c046f3dd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_0ccbf2c0-6146-4c2b-9620-f7647febfe5d" xlink:to="loc_us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1_0a197de8-ebb8-4a2e-bbbe-4785c046f3dd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_f0186fa2-fae6-471f-812b-bd953b4d9b13" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_0ccbf2c0-6146-4c2b-9620-f7647febfe5d" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_f0186fa2-fae6-471f-812b-bd953b4d9b13" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseAndRentalExpense_88e02445-e46d-4df8-980f-a26c255dec37" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LeaseAndRentalExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_0ccbf2c0-6146-4c2b-9620-f7647febfe5d" xlink:to="loc_us-gaap_LeaseAndRentalExpense_88e02445-e46d-4df8-980f-a26c255dec37" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_f308c80b-ff8e-48e1-9671-7524415d4548" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_0ccbf2c0-6146-4c2b-9620-f7647febfe5d" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_f308c80b-ff8e-48e1-9671-7524415d4548" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_1447df4f-e137-439c-bbbe-618fd63b158d" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_f308c80b-ff8e-48e1-9671-7524415d4548" xlink:to="loc_srt_RangeAxis_1447df4f-e137-439c-bbbe-618fd63b158d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_1447df4f-e137-439c-bbbe-618fd63b158d_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_1447df4f-e137-439c-bbbe-618fd63b158d" xlink:to="loc_srt_RangeMember_1447df4f-e137-439c-bbbe-618fd63b158d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_1dcf0c2f-39f6-442a-9cf0-ff62fe07e211" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_1447df4f-e137-439c-bbbe-618fd63b158d" xlink:to="loc_srt_RangeMember_1dcf0c2f-39f6-442a-9cf0-ff62fe07e211" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_ca060fb9-9265-432d-8c9a-c0af3a6e0068" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_1dcf0c2f-39f6-442a-9cf0-ff62fe07e211" xlink:to="loc_srt_MinimumMember_ca060fb9-9265-432d-8c9a-c0af3a6e0068" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_25b8a388-0a88-4177-93aa-34a01f31be30" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_1dcf0c2f-39f6-442a-9cf0-ff62fe07e211" xlink:to="loc_srt_MaximumMember_25b8a388-0a88-4177-93aa-34a01f31be30" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/LeasesSummaryofLeasesDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#LeasesSummaryofLeasesDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/LeasesSummaryofLeasesDetails" xlink:type="extended" id="i067cd807e9f84c9c94131f87c5874b7e_LeasesSummaryofLeasesDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/LeasesComponentsofLeaseCostsDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#LeasesComponentsofLeaseCostsDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/LeasesComponentsofLeaseCostsDetails" xlink:type="extended" id="if331b491c0f4476eaf236781969ebe61_LeasesComponentsofLeaseCostsDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/LeasesMaturitiesofLeaseLiabilitiesDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#LeasesMaturitiesofLeaseLiabilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/LeasesMaturitiesofLeaseLiabilitiesDetails" xlink:type="extended" id="i4779fbe4d55e4e97b52e918791ee4391_LeasesMaturitiesofLeaseLiabilitiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_a18bf814-f624-4088-a407-cdc6d0ae0414" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_fad7b76d-0671-4814-b587-b4f417b71a91" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_a18bf814-f624-4088-a407-cdc6d0ae0414" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_fad7b76d-0671-4814-b587-b4f417b71a91" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_7a9b38c9-8a86-4fcd-9e5d-cf5ea6a61fa9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_a18bf814-f624-4088-a407-cdc6d0ae0414" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_7a9b38c9-8a86-4fcd-9e5d-cf5ea6a61fa9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_4bbc9c0d-7edc-4262-8770-4e3edb804cc6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_a18bf814-f624-4088-a407-cdc6d0ae0414" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_4bbc9c0d-7edc-4262-8770-4e3edb804cc6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_6e8a60bd-300a-40fa-ae85-9d1e49756726" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_a18bf814-f624-4088-a407-cdc6d0ae0414" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_6e8a60bd-300a-40fa-ae85-9d1e49756726" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_a26e33c2-fcdc-4760-bf9c-0b0ae66cc963" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_a18bf814-f624-4088-a407-cdc6d0ae0414" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_a26e33c2-fcdc-4760-bf9c-0b0ae66cc963" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_4582d90a-c6a2-48e7-9786-1f8e9e2c1700" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_a18bf814-f624-4088-a407-cdc6d0ae0414" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_4582d90a-c6a2-48e7-9786-1f8e9e2c1700" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_3e96c0f4-7dbd-4496-aad1-e40a7a49926e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_a18bf814-f624-4088-a407-cdc6d0ae0414" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_3e96c0f4-7dbd-4496-aad1-e40a7a49926e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_3e747933-f079-405b-a85b-776587100c9e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_a18bf814-f624-4088-a407-cdc6d0ae0414" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_3e747933-f079-405b-a85b-776587100c9e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_88e03ecb-f2ce-4ecc-9b81-09c8b755ca55" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_a18bf814-f624-4088-a407-cdc6d0ae0414" xlink:to="loc_us-gaap_OperatingLeaseLiability_88e03ecb-f2ce-4ecc-9b81-09c8b755ca55" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_LesseeOperatingLeaseLiabilityToBePaidAbandonedLeases_fded7b46-6047-44bd-8f51-3351fa088976" xlink:href="amgn-20201231.xsd#amgn_LesseeOperatingLeaseLiabilityToBePaidAbandonedLeases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_a18bf814-f624-4088-a407-cdc6d0ae0414" xlink:to="loc_amgn_LesseeOperatingLeaseLiabilityToBePaidAbandonedLeases_fded7b46-6047-44bd-8f51-3351fa088976" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceived_220e5018-a4d7-4cd7-acfa-1613bf3bf387" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceived"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_a18bf814-f624-4088-a407-cdc6d0ae0414" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceived_220e5018-a4d7-4cd7-acfa-1613bf3bf387" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_4dcc8ab9-d25a-466b-9952-e2209f32388f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_a18bf814-f624-4088-a407-cdc6d0ae0414" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_4dcc8ab9-d25a-466b-9952-e2209f32388f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_c7e18a03-8c9d-41d6-8de4-1eb195d3b165" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_4dcc8ab9-d25a-466b-9952-e2209f32388f" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_c7e18a03-8c9d-41d6-8de4-1eb195d3b165" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_c7e18a03-8c9d-41d6-8de4-1eb195d3b165_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_c7e18a03-8c9d-41d6-8de4-1eb195d3b165" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_c7e18a03-8c9d-41d6-8de4-1eb195d3b165_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_b1c73973-6ad1-406d-a7dc-133e180f96af" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_c7e18a03-8c9d-41d6-8de4-1eb195d3b165" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_b1c73973-6ad1-406d-a7dc-133e180f96af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_AbandonedLeasesMember_cebdb7af-1a4f-4a8d-bdc2-e3de86c23037" xlink:href="amgn-20201231.xsd#amgn_AbandonedLeasesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_b1c73973-6ad1-406d-a7dc-133e180f96af" xlink:to="loc_amgn_AbandonedLeasesMember_cebdb7af-1a4f-4a8d-bdc2-e3de86c23037" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/LeasesCashandNoncashInformationofLeasesDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#LeasesCashandNoncashInformationofLeasesDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/LeasesCashandNoncashInformationofLeasesDetails" xlink:type="extended" id="i32806f08219a493bb424c210ab1903d5_LeasesCashandNoncashInformationofLeasesDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/Othercurrentassetsandaccruedliabilities" xlink:type="simple" xlink:href="amgn-20201231.xsd#Othercurrentassetsandaccruedliabilities"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/Othercurrentassetsandaccruedliabilities" xlink:type="extended" id="ied0039feb83d4be6b7a01edaf0908b44_Othercurrentassetsandaccruedliabilities"/>
  <link:roleRef roleURI="http://www.amgen.com/role/OthercurrentassetsandaccruedliabilitiesTables" xlink:type="simple" xlink:href="amgn-20201231.xsd#OthercurrentassetsandaccruedliabilitiesTables"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/OthercurrentassetsandaccruedliabilitiesTables" xlink:type="extended" id="ia39bf9738a8a48e5bf61deff2127d7e0_OthercurrentassetsandaccruedliabilitiesTables"/>
  <link:roleRef roleURI="http://www.amgen.com/role/OthercurrentassetsandaccruedliabilitiesScheduleofOtherAssetsDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#OthercurrentassetsandaccruedliabilitiesScheduleofOtherAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/OthercurrentassetsandaccruedliabilitiesScheduleofOtherAssetsDetails" xlink:type="extended" id="iddaec3249b7548bea1ec4b967bea8190_OthercurrentassetsandaccruedliabilitiesScheduleofOtherAssetsDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/OthercurrentassetsandaccruedliabilitiesScheduleofAccruedLiabilitiesDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#OthercurrentassetsandaccruedliabilitiesScheduleofAccruedLiabilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/OthercurrentassetsandaccruedliabilitiesScheduleofAccruedLiabilitiesDetails" xlink:type="extended" id="i3157afb923f44f08a46856241e10a87d_OthercurrentassetsandaccruedliabilitiesScheduleofAccruedLiabilitiesDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/Financingarrangements" xlink:type="simple" xlink:href="amgn-20201231.xsd#Financingarrangements"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/Financingarrangements" xlink:type="extended" id="i0734a85cf4174658bca53dbf52b20fe1_Financingarrangements"/>
  <link:roleRef roleURI="http://www.amgen.com/role/FinancingarrangementsTables" xlink:type="simple" xlink:href="amgn-20201231.xsd#FinancingarrangementsTables"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/FinancingarrangementsTables" xlink:type="extended" id="i4d90fd7d51a04282ac16b63be8f6ec86_FinancingarrangementsTables"/>
  <link:roleRef roleURI="http://www.amgen.com/role/FinancingarrangementsPrincipalAmountsandCarryingValueofLongtermBorrowingsDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#FinancingarrangementsPrincipalAmountsandCarryingValueofLongtermBorrowingsDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/FinancingarrangementsPrincipalAmountsandCarryingValueofLongtermBorrowingsDetails" xlink:type="extended" id="i35000b458d61490e902807a5e53e068a_FinancingarrangementsPrincipalAmountsandCarryingValueofLongtermBorrowingsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_a847e05b-a10e-4ad5-980d-d6c411c368fd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_129505db-9fef-4334-a5a5-94f0b0bdc414" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a847e05b-a10e-4ad5-980d-d6c411c368fd" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_129505db-9fef-4334-a5a5-94f0b0bdc414" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_8dd022d5-1f21-4d18-a2b2-b62544d8ebdf" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a847e05b-a10e-4ad5-980d-d6c411c368fd" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_8dd022d5-1f21-4d18-a2b2-b62544d8ebdf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_7456ef78-a2be-4e30-8e78-6ca32d6b85d5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a847e05b-a10e-4ad5-980d-d6c411c368fd" xlink:to="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_7456ef78-a2be-4e30-8e78-6ca32d6b85d5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_PercentageofPrincipalAmountofNotesthatmaybePaidUponOccurrenceofChangeinControlTriggeringEvent_ee619333-0725-47b0-ae54-09fe5c5aed6d" xlink:href="amgn-20201231.xsd#amgn_PercentageofPrincipalAmountofNotesthatmaybePaidUponOccurrenceofChangeinControlTriggeringEvent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a847e05b-a10e-4ad5-980d-d6c411c368fd" xlink:to="loc_amgn_PercentageofPrincipalAmountofNotesthatmaybePaidUponOccurrenceofChangeinControlTriggeringEvent_ee619333-0725-47b0-ae54-09fe5c5aed6d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_DebtInstrumentRedemptionPeriodwithoutPaymentofMakeWholeAmount_cdd8b4c6-067d-47f3-9e64-a52ad19e165f" xlink:href="amgn-20201231.xsd#amgn_DebtInstrumentRedemptionPeriodwithoutPaymentofMakeWholeAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a847e05b-a10e-4ad5-980d-d6c411c368fd" xlink:to="loc_amgn_DebtInstrumentRedemptionPeriodwithoutPaymentofMakeWholeAmount_cdd8b4c6-067d-47f3-9e64-a52ad19e165f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtByCurrentAndNoncurrentAbstract_ea9ed7d0-4edb-4dbe-827a-ccd05b0a6d20" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebtByCurrentAndNoncurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a847e05b-a10e-4ad5-980d-d6c411c368fd" xlink:to="loc_us-gaap_LongTermDebtByCurrentAndNoncurrentAbstract_ea9ed7d0-4edb-4dbe-827a-ccd05b0a6d20" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_76bb419e-2ec0-4f00-a0d5-3ea9a0e69765" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByCurrentAndNoncurrentAbstract_ea9ed7d0-4edb-4dbe-827a-ccd05b0a6d20" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_76bb419e-2ec0-4f00-a0d5-3ea9a0e69765" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_9d1a357e-1e42-4f17-9cd2-a7e3dbc3233b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByCurrentAndNoncurrentAbstract_ea9ed7d0-4edb-4dbe-827a-ccd05b0a6d20" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_9d1a357e-1e42-4f17-9cd2-a7e3dbc3233b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease_591ac7bd-debf-41f5-b0dc-0ba80a8fbd11" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByCurrentAndNoncurrentAbstract_ea9ed7d0-4edb-4dbe-827a-ccd05b0a6d20" xlink:to="loc_us-gaap_HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease_591ac7bd-debf-41f5-b0dc-0ba80a8fbd11" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLongTermDebt_cdeddad0-c5d7-4ffb-adf1-425a61a4eaaf" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherLongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByCurrentAndNoncurrentAbstract_ea9ed7d0-4edb-4dbe-827a-ccd05b0a6d20" xlink:to="loc_us-gaap_OtherLongTermDebt_cdeddad0-c5d7-4ffb-adf1-425a61a4eaaf" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_29d94c3c-8c0f-43fe-986e-a77fe416f09a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByCurrentAndNoncurrentAbstract_ea9ed7d0-4edb-4dbe-827a-ccd05b0a6d20" xlink:to="loc_us-gaap_LongTermDebt_29d94c3c-8c0f-43fe-986e-a77fe416f09a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtCurrent_1705d3a8-13b7-482c-aba8-6931bde85fd4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebtCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByCurrentAndNoncurrentAbstract_ea9ed7d0-4edb-4dbe-827a-ccd05b0a6d20" xlink:to="loc_us-gaap_LongTermDebtCurrent_1705d3a8-13b7-482c-aba8-6931bde85fd4" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_0d11fa0f-2fd0-4427-9e8b-fd01906bf1a3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByCurrentAndNoncurrentAbstract_ea9ed7d0-4edb-4dbe-827a-ccd05b0a6d20" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_0d11fa0f-2fd0-4427-9e8b-fd01906bf1a3" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_ebad9515-ca3a-431d-8986-7c3532bd4216" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a847e05b-a10e-4ad5-980d-d6c411c368fd" xlink:to="loc_us-gaap_DebtInstrumentTable_ebad9515-ca3a-431d-8986-7c3532bd4216" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_ca4d0b16-5e2c-4a8a-a279-78cebbade161" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_ebad9515-ca3a-431d-8986-7c3532bd4216" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_ca4d0b16-5e2c-4a8a-a279-78cebbade161" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_ca4d0b16-5e2c-4a8a-a279-78cebbade161_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_ca4d0b16-5e2c-4a8a-a279-78cebbade161" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_ca4d0b16-5e2c-4a8a-a279-78cebbade161_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_dfb0307c-3631-4e00-8b5e-ec34e1d784cf" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_ca4d0b16-5e2c-4a8a-a279-78cebbade161" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_dfb0307c-3631-4e00-8b5e-ec34e1d784cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableToBanksMember_744d2ad8-4eaf-44c4-a20f-6e561a167d51" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesPayableToBanksMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_dfb0307c-3631-4e00-8b5e-ec34e1d784cf" xlink:to="loc_us-gaap_NotesPayableToBanksMember_744d2ad8-4eaf-44c4-a20f-6e561a167d51" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesPayableMember_5520e2c3-1898-43dc-ad67-624df70e4035" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_dfb0307c-3631-4e00-8b5e-ec34e1d784cf" xlink:to="loc_us-gaap_DebtSecuritiesPayableMember_5520e2c3-1898-43dc-ad67-624df70e4035" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_d778eb6d-17c3-4410-875a-5e6fd0a6d209" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_ebad9515-ca3a-431d-8986-7c3532bd4216" xlink:to="loc_us-gaap_DebtInstrumentAxis_d778eb6d-17c3-4410-875a-5e6fd0a6d209" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_d778eb6d-17c3-4410-875a-5e6fd0a6d209_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_d778eb6d-17c3-4410-875a-5e6fd0a6d209" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_d778eb6d-17c3-4410-875a-5e6fd0a6d209_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_d778eb6d-17c3-4410-875a-5e6fd0a6d209" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FourPointFiveZeroPercentNotesDue2020Member_6ae3111e-bc8a-4f7d-9f56-9276889b77c9" xlink:href="amgn-20201231.xsd#amgn_FourPointFiveZeroPercentNotesDue2020Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_FourPointFiveZeroPercentNotesDue2020Member_6ae3111e-bc8a-4f7d-9f56-9276889b77c9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointOneTwoFivePercentNotesDueTwoZeroTwoZeroMember_a264a1c0-3115-4d81-8e8f-82cd0fb528a5" xlink:href="amgn-20201231.xsd#amgn_TwoPointOneTwoFivePercentNotesDueTwoZeroTwoZeroMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_TwoPointOneTwoFivePercentNotesDueTwoZeroTwoZeroMember_a264a1c0-3115-4d81-8e8f-82cd0fb528a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FloatingRateNotesDue2020Member_571380db-7692-447e-b6cb-518d858ba00e" xlink:href="amgn-20201231.xsd#amgn_FloatingRateNotesDue2020Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_FloatingRateNotesDue2020Member_571380db-7692-447e-b6cb-518d858ba00e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointTwoZeroNotesDue2020Member_6622fdd7-b533-4c80-897a-2a3b49f46ff3" xlink:href="amgn-20201231.xsd#amgn_TwoPointTwoZeroNotesDue2020Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_TwoPointTwoZeroNotesDue2020Member_6622fdd7-b533-4c80-897a-2a3b49f46ff3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ThreePointFourFivePercentNotesDue2020Member_d9c0b288-4370-4dcd-ac1d-c94a0cd9a577" xlink:href="amgn-20201231.xsd#amgn_ThreePointFourFivePercentNotesDue2020Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_ThreePointFourFivePercentNotesDue2020Member_d9c0b288-4370-4dcd-ac1d-c94a0cd9a577" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FourPointOneZeroPercentNotesDue2021Member_b3e959d6-c8c8-47b2-aba5-242996da242e" xlink:href="amgn-20201231.xsd#amgn_FourPointOneZeroPercentNotesDue2021Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_FourPointOneZeroPercentNotesDue2021Member_b3e959d6-c8c8-47b2-aba5-242996da242e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_OnePointEightFivePercentNotesDueTwoZeroTwoOneMember_49aadc88-c0a9-4d62-bbc4-55b5ca352651" xlink:href="amgn-20201231.xsd#amgn_OnePointEightFivePercentNotesDueTwoZeroTwoOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_OnePointEightFivePercentNotesDueTwoZeroTwoOneMember_49aadc88-c0a9-4d62-bbc4-55b5ca352651" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ThreePointEightSevenFivePercentNotesDue2021Member_b8cccb40-ca15-4a16-a57a-73e54460f5f5" xlink:href="amgn-20201231.xsd#amgn_ThreePointEightSevenFivePercentNotesDue2021Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_ThreePointEightSevenFivePercentNotesDue2021Member_b8cccb40-ca15-4a16-a57a-73e54460f5f5" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_OnePointTwoFivePercentEuroNotesdueTwoZeroTwoTwoMember_365f0df7-1dd6-4f46-bae0-03daa5b69ac1" xlink:href="amgn-20201231.xsd#amgn_OnePointTwoFivePercentEuroNotesdueTwoZeroTwoTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_OnePointTwoFivePercentEuroNotesdueTwoZeroTwoTwoMember_365f0df7-1dd6-4f46-bae0-03daa5b69ac1" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointSevenZeroPercentNotesDueTwoZeroTwoTwoMember_5d3a605c-9e2a-48cb-b762-0b60fd5ef2cd" xlink:href="amgn-20201231.xsd#amgn_TwoPointSevenZeroPercentNotesDueTwoZeroTwoTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_TwoPointSevenZeroPercentNotesDueTwoZeroTwoTwoMember_5d3a605c-9e2a-48cb-b762-0b60fd5ef2cd" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointSixFiveNotesDue2022Member_52a28796-5f2b-414e-a304-63733430f9da" xlink:href="amgn-20201231.xsd#amgn_TwoPointSixFiveNotesDue2022Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_TwoPointSixFiveNotesDue2022Member_52a28796-5f2b-414e-a304-63733430f9da" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ThreePointSixTwoFivePercentNotesDue2022Member_0a9d1e07-aadd-4827-8106-765a1888fa9c" xlink:href="amgn-20201231.xsd#amgn_ThreePointSixTwoFivePercentNotesDue2022Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_ThreePointSixTwoFivePercentNotesDue2022Member_0a9d1e07-aadd-4827-8106-765a1888fa9c" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ZeroPointFortyOnePercentSwissFrancBondsDueTwoThousandTwentyThreeMember_fb825b1e-c4c1-4709-8e3c-6920b8dd1284" xlink:href="amgn-20201231.xsd#amgn_ZeroPointFortyOnePercentSwissFrancBondsDueTwoThousandTwentyThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_ZeroPointFortyOnePercentSwissFrancBondsDueTwoThousandTwentyThreeMember_fb825b1e-c4c1-4709-8e3c-6920b8dd1284" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointTwoFivePercentNotesDueTwoZeroTwoThreeMember_1a9544fd-e06b-46b9-8f3a-f75ace4b3295" xlink:href="amgn-20201231.xsd#amgn_TwoPointTwoFivePercentNotesDueTwoZeroTwoThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_TwoPointTwoFivePercentNotesDueTwoZeroTwoThreeMember_1a9544fd-e06b-46b9-8f3a-f75ace4b3295" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ThreePointSixTwoFivePercentNotesDue2024Member_37879d66-3d08-416a-a4f7-bc77b30c9bf7" xlink:href="amgn-20201231.xsd#amgn_ThreePointSixTwoFivePercentNotesDue2024Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_ThreePointSixTwoFivePercentNotesDue2024Member_37879d66-3d08-416a-a4f7-bc77b30c9bf7" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_OnePointNineZeroPercentNotesDueTwoZeroTwoFiveMember_d0adfbc5-f8e1-40c2-a98c-b72078c261fc" xlink:href="amgn-20201231.xsd#amgn_OnePointNineZeroPercentNotesDueTwoZeroTwoFiveMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_OnePointNineZeroPercentNotesDueTwoZeroTwoFiveMember_d0adfbc5-f8e1-40c2-a98c-b72078c261fc" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ThreePointOneTwoFivePercentNotesDueTwoZeroTwoFiveMember_2cf0ec25-afd2-4b64-be7f-904a6e6c4554" xlink:href="amgn-20201231.xsd#amgn_ThreePointOneTwoFivePercentNotesDueTwoZeroTwoFiveMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_ThreePointOneTwoFivePercentNotesDueTwoZeroTwoFiveMember_2cf0ec25-afd2-4b64-be7f-904a6e6c4554" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPercentEuroNotesDueTwoThousandTwentySixMember_993683f9-8f05-4a8d-9fa8-13324f06af05" xlink:href="amgn-20201231.xsd#amgn_TwoPercentEuroNotesDueTwoThousandTwentySixMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_TwoPercentEuroNotesDueTwoThousandTwentySixMember_993683f9-8f05-4a8d-9fa8-13324f06af05" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointSixZeroNotesDueTwoZeroTwoSixMember_7d696b75-7b8d-49ce-9577-4759183691f9" xlink:href="amgn-20201231.xsd#amgn_TwoPointSixZeroNotesDueTwoZeroTwoSixMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_TwoPointSixZeroNotesDueTwoZeroTwoSixMember_7d696b75-7b8d-49ce-9577-4759183691f9" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FivePointFiveZeroPercentPoundSterlingNotesDue2026Member_8413cf73-828b-4b4e-97f7-7037a970e631" xlink:href="amgn-20201231.xsd#amgn_FivePointFiveZeroPercentPoundSterlingNotesDue2026Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_FivePointFiveZeroPercentPoundSterlingNotesDue2026Member_8413cf73-828b-4b4e-97f7-7037a970e631" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointTwoZeroPercentNotesDueTwoZeroTwoSevenMember_6e7520cc-7861-4180-99aa-7f4b3d3a23f5" xlink:href="amgn-20201231.xsd#amgn_TwoPointTwoZeroPercentNotesDueTwoZeroTwoSevenMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_TwoPointTwoZeroPercentNotesDueTwoZeroTwoSevenMember_6e7520cc-7861-4180-99aa-7f4b3d3a23f5" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ThreePointTwoZeroNotesDue2027Member_b830c557-f639-458f-8e62-2c504dad8182" xlink:href="amgn-20201231.xsd#amgn_ThreePointTwoZeroNotesDue2027Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_ThreePointTwoZeroNotesDue2027Member_b830c557-f639-458f-8e62-2c504dad8182" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FourPercentPoundSterlingNotesDue2029Member_f1aa36ed-ffb5-4cad-a9fd-66d306c952a0" xlink:href="amgn-20201231.xsd#amgn_FourPercentPoundSterlingNotesDue2029Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_FourPercentPoundSterlingNotesDue2029Member_f1aa36ed-ffb5-4cad-a9fd-66d306c952a0" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointFourFivePercentNotesDue2030Member_e50ae0c5-5717-4334-a15f-50053c377ae7" xlink:href="amgn-20201231.xsd#amgn_TwoPointFourFivePercentNotesDue2030Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_TwoPointFourFivePercentNotesDue2030Member_e50ae0c5-5717-4334-a15f-50053c377ae7" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointThreeZeroPercentNotesDue2031Member_f7b8053c-8403-4cbc-9e6f-ba976fc18039" xlink:href="amgn-20201231.xsd#amgn_TwoPointThreeZeroPercentNotesDue2031Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_TwoPointThreeZeroPercentNotesDue2031Member_f7b8053c-8403-4cbc-9e6f-ba976fc18039" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_SixPointThreeSevenFivePercentNotesDue2037Member_a80e2d32-01ad-4892-b094-8a0883b800e4" xlink:href="amgn-20201231.xsd#amgn_SixPointThreeSevenFivePercentNotesDue2037Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_SixPointThreeSevenFivePercentNotesDue2037Member_a80e2d32-01ad-4892-b094-8a0883b800e4" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_SixPointNineZeroPercentNotesDue2038Member_e2ab152a-0c0e-4d8a-b62d-0f37c22ef027" xlink:href="amgn-20201231.xsd#amgn_SixPointNineZeroPercentNotesDue2038Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_SixPointNineZeroPercentNotesDue2038Member_e2ab152a-0c0e-4d8a-b62d-0f37c22ef027" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_SixPointFourZeroPercentNotesDue2039Member_04b9f98d-23b8-46a2-bfb3-f546b52bbdf8" xlink:href="amgn-20201231.xsd#amgn_SixPointFourZeroPercentNotesDue2039Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_SixPointFourZeroPercentNotesDue2039Member_04b9f98d-23b8-46a2-bfb3-f546b52bbdf8" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ThreePointOneFivePercentNotesDue2040Member_7cbc9b01-541a-4095-b1e2-0e663c1d6b3c" xlink:href="amgn-20201231.xsd#amgn_ThreePointOneFivePercentNotesDue2040Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_ThreePointOneFivePercentNotesDue2040Member_7cbc9b01-541a-4095-b1e2-0e663c1d6b3c" xlink:type="arc" order="28"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FivePointSevenFivePercentNotesDue2040Member_80e34ce9-c70a-45b4-b8b7-5fc5757920b8" xlink:href="amgn-20201231.xsd#amgn_FivePointSevenFivePercentNotesDue2040Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_FivePointSevenFivePercentNotesDue2040Member_80e34ce9-c70a-45b4-b8b7-5fc5757920b8" xlink:type="arc" order="29"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FourPointNineFivePercentNotesDue2041Member_b18d122a-a288-4b55-9479-484ae5eda19e" xlink:href="amgn-20201231.xsd#amgn_FourPointNineFivePercentNotesDue2041Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_FourPointNineFivePercentNotesDue2041Member_b18d122a-a288-4b55-9479-484ae5eda19e" xlink:type="arc" order="30"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FivePointOneFivePercentNotesDue2041Member_22accdc2-4f49-4eb0-a425-5a785d6e0894" xlink:href="amgn-20201231.xsd#amgn_FivePointOneFivePercentNotesDue2041Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_FivePointOneFivePercentNotesDue2041Member_22accdc2-4f49-4eb0-a425-5a785d6e0894" xlink:type="arc" order="31"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FivePointSixFivePercentNotesDue2042Member_c1fac421-ff6e-4797-8734-85d41a5fab21" xlink:href="amgn-20201231.xsd#amgn_FivePointSixFivePercentNotesDue2042Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_FivePointSixFivePercentNotesDue2042Member_c1fac421-ff6e-4797-8734-85d41a5fab21" xlink:type="arc" order="32"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FivePointThreeSevenFivePercentNotesDue2043Member_f28de94d-64da-413d-8a8b-623d132e1b16" xlink:href="amgn-20201231.xsd#amgn_FivePointThreeSevenFivePercentNotesDue2043Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_FivePointThreeSevenFivePercentNotesDue2043Member_f28de94d-64da-413d-8a8b-623d132e1b16" xlink:type="arc" order="33"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FourPointFourZeroPercentNotesDueTwoZeroFourFiveMember_1df2b531-3532-44a4-8270-6bda71be1ee9" xlink:href="amgn-20201231.xsd#amgn_FourPointFourZeroPercentNotesDueTwoZeroFourFiveMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_FourPointFourZeroPercentNotesDueTwoZeroFourFiveMember_1df2b531-3532-44a4-8270-6bda71be1ee9" xlink:type="arc" order="34"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FourPointFiveSixThreePercentNotesDueTwoZeroFourEightMember_60d40717-818a-4aba-98c4-4ff4f4235540" xlink:href="amgn-20201231.xsd#amgn_FourPointFiveSixThreePercentNotesDueTwoZeroFourEightMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_FourPointFiveSixThreePercentNotesDueTwoZeroFourEightMember_60d40717-818a-4aba-98c4-4ff4f4235540" xlink:type="arc" order="35"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ThreePointThreeSevenFivePercentNotesDue2050Member_d114519a-c079-443e-b443-2de07947f031" xlink:href="amgn-20201231.xsd#amgn_ThreePointThreeSevenFivePercentNotesDue2050Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_ThreePointThreeSevenFivePercentNotesDue2050Member_d114519a-c079-443e-b443-2de07947f031" xlink:type="arc" order="36"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FourPointSixSixThreePercentNotesDueTwoZeroFiveOneMember_a909165e-303e-44d5-a468-41da440af8f4" xlink:href="amgn-20201231.xsd#amgn_FourPointSixSixThreePercentNotesDueTwoZeroFiveOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_FourPointSixSixThreePercentNotesDueTwoZeroFiveOneMember_a909165e-303e-44d5-a468-41da440af8f4" xlink:type="arc" order="37"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointSevenSevenPercentNotesDueTwoZeroFiveThreeMember_3c7578fc-0a93-476b-a8c8-06fe5178e48a" xlink:href="amgn-20201231.xsd#amgn_TwoPointSevenSevenPercentNotesDueTwoZeroFiveThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_TwoPointSevenSevenPercentNotesDueTwoZeroFiveThreeMember_3c7578fc-0a93-476b-a8c8-06fe5178e48a" xlink:type="arc" order="38"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_OtherNotesDue2097Member_053b62de-973e-4d6c-a1ae-a5bc761f0318" xlink:href="amgn-20201231.xsd#amgn_OtherNotesDue2097Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_d3623d5e-3e12-496c-9da0-325c340e1527" xlink:to="loc_amgn_OtherNotesDue2097Member_053b62de-973e-4d6c-a1ae-a5bc761f0318" xlink:type="arc" order="39"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_e1bcef9d-8a5a-4009-a278-bc35c80ea555" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_ebad9515-ca3a-431d-8986-7c3532bd4216" xlink:to="loc_srt_RangeAxis_e1bcef9d-8a5a-4009-a278-bc35c80ea555" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_e1bcef9d-8a5a-4009-a278-bc35c80ea555_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_e1bcef9d-8a5a-4009-a278-bc35c80ea555" xlink:to="loc_srt_RangeMember_e1bcef9d-8a5a-4009-a278-bc35c80ea555_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_15903922-d2e1-4d13-910e-aeacc7bcdce5" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_e1bcef9d-8a5a-4009-a278-bc35c80ea555" xlink:to="loc_srt_RangeMember_15903922-d2e1-4d13-910e-aeacc7bcdce5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_c4ff281a-1935-4460-b3bb-696893819d4d" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_15903922-d2e1-4d13-910e-aeacc7bcdce5" xlink:to="loc_srt_MinimumMember_c4ff281a-1935-4460-b3bb-696893819d4d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_b61a8812-cdc8-41d8-9906-1d7e2d4b2f49" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_15903922-d2e1-4d13-910e-aeacc7bcdce5" xlink:to="loc_srt_MaximumMember_b61a8812-cdc8-41d8-9906-1d7e2d4b2f49" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/FinancingarrangementsDebtIssuancesDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#FinancingarrangementsDebtIssuancesDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/FinancingarrangementsDebtIssuancesDetails" xlink:type="extended" id="i7f340df1940d4c478fbc3d8d770c3c08_FinancingarrangementsDebtIssuancesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_bd83ae79-2bae-42f3-8b4d-cecae85f1a61" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_d11811e7-c1c4-4d14-af61-0c04a316f986" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bd83ae79-2bae-42f3-8b4d-cecae85f1a61" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_d11811e7-c1c4-4d14-af61-0c04a316f986" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_e31dbfa4-9646-41b1-bab3-95b449d6b7ce" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bd83ae79-2bae-42f3-8b4d-cecae85f1a61" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_e31dbfa4-9646-41b1-bab3-95b449d6b7ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_MaximumBorrowingCapacityUnderCommercialPaper_bde57b04-9a99-41e7-8630-ee660c3a2c17" xlink:href="amgn-20201231.xsd#amgn_MaximumBorrowingCapacityUnderCommercialPaper"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bd83ae79-2bae-42f3-8b4d-cecae85f1a61" xlink:to="loc_amgn_MaximumBorrowingCapacityUnderCommercialPaper_bde57b04-9a99-41e7-8630-ee660c3a2c17" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_c50b09f2-f9fd-4edc-8ee6-7ca2b4084391" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bd83ae79-2bae-42f3-8b4d-cecae85f1a61" xlink:to="loc_us-gaap_DebtInstrumentTable_c50b09f2-f9fd-4edc-8ee6-7ca2b4084391" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_c92c74de-69de-468f-86e6-4277337b0c64" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_c50b09f2-f9fd-4edc-8ee6-7ca2b4084391" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_c92c74de-69de-468f-86e6-4277337b0c64" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_c92c74de-69de-468f-86e6-4277337b0c64_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_c92c74de-69de-468f-86e6-4277337b0c64" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_c92c74de-69de-468f-86e6-4277337b0c64_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_0a95b286-ab16-4455-a857-e3ae85f6ab2f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_c92c74de-69de-468f-86e6-4277337b0c64" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_0a95b286-ab16-4455-a857-e3ae85f6ab2f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableToBanksMember_25ec19bc-6451-49d9-90d2-c8d3b514535b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesPayableToBanksMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_0a95b286-ab16-4455-a857-e3ae85f6ab2f" xlink:to="loc_us-gaap_NotesPayableToBanksMember_25ec19bc-6451-49d9-90d2-c8d3b514535b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_119e4a3a-c474-4a37-a7d6-123cd571b4f9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_c50b09f2-f9fd-4edc-8ee6-7ca2b4084391" xlink:to="loc_us-gaap_DebtInstrumentAxis_119e4a3a-c474-4a37-a7d6-123cd571b4f9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_119e4a3a-c474-4a37-a7d6-123cd571b4f9_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_119e4a3a-c474-4a37-a7d6-123cd571b4f9" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_119e4a3a-c474-4a37-a7d6-123cd571b4f9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_7437af23-ef56-4f57-afee-005ada5e135d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_119e4a3a-c474-4a37-a7d6-123cd571b4f9" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_7437af23-ef56-4f57-afee-005ada5e135d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_OnePointNineZeroPercentNotesDueTwoZeroTwoFiveMember_5a52850b-fb6d-4c15-81a9-531fd2dcf761" xlink:href="amgn-20201231.xsd#amgn_OnePointNineZeroPercentNotesDueTwoZeroTwoFiveMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7437af23-ef56-4f57-afee-005ada5e135d" xlink:to="loc_amgn_OnePointNineZeroPercentNotesDueTwoZeroTwoFiveMember_5a52850b-fb6d-4c15-81a9-531fd2dcf761" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointTwoZeroPercentNotesDueTwoZeroTwoSevenMember_8d6b2df0-3214-497d-a248-0277c41a1499" xlink:href="amgn-20201231.xsd#amgn_TwoPointTwoZeroPercentNotesDueTwoZeroTwoSevenMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7437af23-ef56-4f57-afee-005ada5e135d" xlink:to="loc_amgn_TwoPointTwoZeroPercentNotesDueTwoZeroTwoSevenMember_8d6b2df0-3214-497d-a248-0277c41a1499" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointFourFivePercentNotesDue2030Member_ab5b332d-05e4-4957-9d2a-e83afb9b4eb2" xlink:href="amgn-20201231.xsd#amgn_TwoPointFourFivePercentNotesDue2030Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7437af23-ef56-4f57-afee-005ada5e135d" xlink:to="loc_amgn_TwoPointFourFivePercentNotesDue2030Member_ab5b332d-05e4-4957-9d2a-e83afb9b4eb2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ThreePointOneFivePercentNotesDue2040Member_4722970d-53bc-4e02-9680-a2f0960f3b2d" xlink:href="amgn-20201231.xsd#amgn_ThreePointOneFivePercentNotesDue2040Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7437af23-ef56-4f57-afee-005ada5e135d" xlink:to="loc_amgn_ThreePointOneFivePercentNotesDue2040Member_4722970d-53bc-4e02-9680-a2f0960f3b2d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ThreePointThreeSevenFivePercentNotesDue2050Member_5f04ed14-28ac-462f-9203-9c973e0792c1" xlink:href="amgn-20201231.xsd#amgn_ThreePointThreeSevenFivePercentNotesDue2050Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7437af23-ef56-4f57-afee-005ada5e135d" xlink:to="loc_amgn_ThreePointThreeSevenFivePercentNotesDue2050Member_5f04ed14-28ac-462f-9203-9c973e0792c1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointThreeZeroPercentNotesDue2031Member_14d56945-7177-4483-bdaa-6abe5c82a9e2" xlink:href="amgn-20201231.xsd#amgn_TwoPointThreeZeroPercentNotesDue2031Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7437af23-ef56-4f57-afee-005ada5e135d" xlink:to="loc_amgn_TwoPointThreeZeroPercentNotesDue2031Member_14d56945-7177-4483-bdaa-6abe5c82a9e2" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/FinancingarrangementsDebtRepaymentsDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#FinancingarrangementsDebtRepaymentsDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/FinancingarrangementsDebtRepaymentsDetails" xlink:type="extended" id="i5ec394c048e247a1a6c733087a0b5a9f_FinancingarrangementsDebtRepaymentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_cc56e598-824a-431a-bb93-2813ffb6596b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfLongTermDebt_c95b9ab8-9cec-4c33-adff-0669a4df586b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RepaymentsOfLongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cc56e598-824a-431a-bb93-2813ffb6596b" xlink:to="loc_us-gaap_RepaymentsOfLongTermDebt_c95b9ab8-9cec-4c33-adff-0669a4df586b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_8105ba25-0ea3-4781-9d0b-da4a1d383613" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cc56e598-824a-431a-bb93-2813ffb6596b" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_8105ba25-0ea3-4781-9d0b-da4a1d383613" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebt_24f0bdfa-8cbe-4a1c-915c-f7e00d32dc50" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cc56e598-824a-431a-bb93-2813ffb6596b" xlink:to="loc_us-gaap_InterestExpenseDebt_24f0bdfa-8cbe-4a1c-915c-f7e00d32dc50" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_cb3c6722-d080-4650-9d74-07cfb5910fae" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_cc56e598-824a-431a-bb93-2813ffb6596b" xlink:to="loc_us-gaap_DebtInstrumentTable_cb3c6722-d080-4650-9d74-07cfb5910fae" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_547cf410-e39c-4bfe-8c2f-5bc714926d47" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_cb3c6722-d080-4650-9d74-07cfb5910fae" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_547cf410-e39c-4bfe-8c2f-5bc714926d47" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_547cf410-e39c-4bfe-8c2f-5bc714926d47_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_547cf410-e39c-4bfe-8c2f-5bc714926d47" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_547cf410-e39c-4bfe-8c2f-5bc714926d47_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_9e13f41c-f267-41ae-9b6f-9f52af57918c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_547cf410-e39c-4bfe-8c2f-5bc714926d47" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_9e13f41c-f267-41ae-9b6f-9f52af57918c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableToBanksMember_f3d629a0-8ac3-4c37-a628-dddde7bdedb9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesPayableToBanksMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_9e13f41c-f267-41ae-9b6f-9f52af57918c" xlink:to="loc_us-gaap_NotesPayableToBanksMember_f3d629a0-8ac3-4c37-a628-dddde7bdedb9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_4483a9a6-f9af-4dbe-9349-b563bd907119" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_cb3c6722-d080-4650-9d74-07cfb5910fae" xlink:to="loc_us-gaap_DebtInstrumentAxis_4483a9a6-f9af-4dbe-9349-b563bd907119" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_4483a9a6-f9af-4dbe-9349-b563bd907119_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_4483a9a6-f9af-4dbe-9349-b563bd907119" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_4483a9a6-f9af-4dbe-9349-b563bd907119_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_2244aba8-1c7e-4ef9-b9ad-b8eb42c73f24" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_4483a9a6-f9af-4dbe-9349-b563bd907119" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_2244aba8-1c7e-4ef9-b9ad-b8eb42c73f24" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointTwoZeroPercentNotesDue2019Member_ff0b21db-634c-41e1-afff-82769dd48f5b" xlink:href="amgn-20201231.xsd#amgn_TwoPointTwoZeroPercentNotesDue2019Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2244aba8-1c7e-4ef9-b9ad-b8eb42c73f24" xlink:to="loc_amgn_TwoPointTwoZeroPercentNotesDue2019Member_ff0b21db-634c-41e1-afff-82769dd48f5b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FivePointSevenZeroPercentNotesDue2019Member_7caf90cf-f427-42ea-98ca-7688ceea19fc" xlink:href="amgn-20201231.xsd#amgn_FivePointSevenZeroPercentNotesDue2019Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2244aba8-1c7e-4ef9-b9ad-b8eb42c73f24" xlink:to="loc_amgn_FivePointSevenZeroPercentNotesDue2019Member_7caf90cf-f427-42ea-98ca-7688ceea19fc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointOneTwoFivePercentEuroNotesDue2019Member_d14e3ba7-d10f-4d6f-afe1-6cfda169f8a5" xlink:href="amgn-20201231.xsd#amgn_TwoPointOneTwoFivePercentEuroNotesDue2019Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2244aba8-1c7e-4ef9-b9ad-b8eb42c73f24" xlink:to="loc_amgn_TwoPointOneTwoFivePercentEuroNotesDue2019Member_d14e3ba7-d10f-4d6f-afe1-6cfda169f8a5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_OnePointNineZeroNotesDue2019Member_01f44286-da46-4eeb-83f9-152542a33fad" xlink:href="amgn-20201231.xsd#amgn_OnePointNineZeroNotesDue2019Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2244aba8-1c7e-4ef9-b9ad-b8eb42c73f24" xlink:to="loc_amgn_OnePointNineZeroNotesDue2019Member_01f44286-da46-4eeb-83f9-152542a33fad" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FloatingRateNotesDue2019Member_7470ff02-2ac3-433e-b81c-44d4a1608116" xlink:href="amgn-20201231.xsd#amgn_FloatingRateNotesDue2019Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2244aba8-1c7e-4ef9-b9ad-b8eb42c73f24" xlink:to="loc_amgn_FloatingRateNotesDue2019Member_7470ff02-2ac3-433e-b81c-44d4a1608116" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_SixPointOneFivePercentNotesDue2018Member_1fff0c5e-7dc5-45a1-9b22-240b75a17cb1" xlink:href="amgn-20201231.xsd#amgn_SixPointOneFivePercentNotesDue2018Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2244aba8-1c7e-4ef9-b9ad-b8eb42c73f24" xlink:to="loc_amgn_SixPointOneFivePercentNotesDue2018Member_1fff0c5e-7dc5-45a1-9b22-240b75a17cb1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FourPointThreeSevenFivePercentEuroNotesDue2018Member_28d35a1a-8763-43c1-aca0-279c44541e50" xlink:href="amgn-20201231.xsd#amgn_FourPointThreeSevenFivePercentEuroNotesDue2018Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2244aba8-1c7e-4ef9-b9ad-b8eb42c73f24" xlink:to="loc_amgn_FourPointThreeSevenFivePercentEuroNotesDue2018Member_28d35a1a-8763-43c1-aca0-279c44541e50" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FourPointFiveZeroPercentNotesDue2020Member_f0c3630f-ccc6-42e4-aefb-a2c81db881da" xlink:href="amgn-20201231.xsd#amgn_FourPointFiveZeroPercentNotesDue2020Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2244aba8-1c7e-4ef9-b9ad-b8eb42c73f24" xlink:to="loc_amgn_FourPointFiveZeroPercentNotesDue2020Member_f0c3630f-ccc6-42e4-aefb-a2c81db881da" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointOneTwoFivePercentNotesDueTwoZeroTwoZeroMember_00f983fd-8f3a-43ff-aaa2-20bca9be7aa4" xlink:href="amgn-20201231.xsd#amgn_TwoPointOneTwoFivePercentNotesDueTwoZeroTwoZeroMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2244aba8-1c7e-4ef9-b9ad-b8eb42c73f24" xlink:to="loc_amgn_TwoPointOneTwoFivePercentNotesDueTwoZeroTwoZeroMember_00f983fd-8f3a-43ff-aaa2-20bca9be7aa4" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointTwoZeroNotesDue2020Member_869ef4cb-e81d-4c54-8a83-9c1bbba340e9" xlink:href="amgn-20201231.xsd#amgn_TwoPointTwoZeroNotesDue2020Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2244aba8-1c7e-4ef9-b9ad-b8eb42c73f24" xlink:to="loc_amgn_TwoPointTwoZeroNotesDue2020Member_869ef4cb-e81d-4c54-8a83-9c1bbba340e9" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ThreePointFourFivePercentNotesDue2020Member_fd26c5d9-bbc3-48dc-bdb5-9b8c3ded9b55" xlink:href="amgn-20201231.xsd#amgn_ThreePointFourFivePercentNotesDue2020Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2244aba8-1c7e-4ef9-b9ad-b8eb42c73f24" xlink:to="loc_amgn_ThreePointFourFivePercentNotesDue2020Member_fd26c5d9-bbc3-48dc-bdb5-9b8c3ded9b55" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FourPointOneZeroPercentNotesDue2021Member_7b211aa8-4cb6-448c-9a8e-221c18eebf6d" xlink:href="amgn-20201231.xsd#amgn_FourPointOneZeroPercentNotesDue2021Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2244aba8-1c7e-4ef9-b9ad-b8eb42c73f24" xlink:to="loc_amgn_FourPointOneZeroPercentNotesDue2021Member_7b211aa8-4cb6-448c-9a8e-221c18eebf6d" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_OnePointEightFivePercentNotesDueTwoZeroTwoOneMember_a766336c-9352-4d96-ab4b-76ea23a009e2" xlink:href="amgn-20201231.xsd#amgn_OnePointEightFivePercentNotesDueTwoZeroTwoOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2244aba8-1c7e-4ef9-b9ad-b8eb42c73f24" xlink:to="loc_amgn_OnePointEightFivePercentNotesDueTwoZeroTwoOneMember_a766336c-9352-4d96-ab4b-76ea23a009e2" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ThreePointEightSevenFivePercentNotesDue2021Member_3a8411ba-3bc2-4fd3-a916-9b8d5bd88381" xlink:href="amgn-20201231.xsd#amgn_ThreePointEightSevenFivePercentNotesDue2021Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2244aba8-1c7e-4ef9-b9ad-b8eb42c73f24" xlink:to="loc_amgn_ThreePointEightSevenFivePercentNotesDue2021Member_3a8411ba-3bc2-4fd3-a916-9b8d5bd88381" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FloatingRateNotesDue2020Member_3ac3a31a-6f2c-41ea-8b4f-f050fea4cc51" xlink:href="amgn-20201231.xsd#amgn_FloatingRateNotesDue2020Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2244aba8-1c7e-4ef9-b9ad-b8eb42c73f24" xlink:to="loc_amgn_FloatingRateNotesDue2020Member_3ac3a31a-6f2c-41ea-8b4f-f050fea4cc51" xlink:type="arc" order="14"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/FinancingarrangementsInterestRateandCrosscurrencySwapsDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#FinancingarrangementsInterestRateandCrosscurrencySwapsDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/FinancingarrangementsInterestRateandCrosscurrencySwapsDetails" xlink:type="extended" id="iab12e016af634cfcacf9886a16e0f65c_FinancingarrangementsInterestRateandCrosscurrencySwapsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_47f20138-adfc-4ba1-9412-716b81278359" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_672bed2b-847e-4d61-8fc5-6efcab2da394" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_47f20138-adfc-4ba1-9412-716b81278359" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_672bed2b-847e-4d61-8fc5-6efcab2da394" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeBasisSpreadOnVariableRate_2cf6f9e8-ef45-4e37-aee5-ade863230eff" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeBasisSpreadOnVariableRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_47f20138-adfc-4ba1-9412-716b81278359" xlink:to="loc_us-gaap_DerivativeBasisSpreadOnVariableRate_2cf6f9e8-ef45-4e37-aee5-ade863230eff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_adb66a7f-cd50-4a72-8a21-cfca41a3138a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_47f20138-adfc-4ba1-9412-716b81278359" xlink:to="loc_us-gaap_DerivativeNotionalAmount_adb66a7f-cd50-4a72-8a21-cfca41a3138a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_DerivativeNotionalAmountAmountTerminated_0c228e2f-cff3-4e7d-b4a7-306049f068d3" xlink:href="amgn-20201231.xsd#amgn_DerivativeNotionalAmountAmountTerminated"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_47f20138-adfc-4ba1-9412-716b81278359" xlink:to="loc_amgn_DerivativeNotionalAmountAmountTerminated_0c228e2f-cff3-4e7d-b4a7-306049f068d3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_f0d7456c-5dd1-4597-8025-a89ea76ab622" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_47f20138-adfc-4ba1-9412-716b81278359" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_f0d7456c-5dd1-4597-8025-a89ea76ab622" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_Ratedifferenceinaninterestrateswaprelationship_4e8a3fc7-ca51-4737-95c6-c33918eed3b8" xlink:href="amgn-20201231.xsd#amgn_Ratedifferenceinaninterestrateswaprelationship"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_47f20138-adfc-4ba1-9412-716b81278359" xlink:to="loc_amgn_Ratedifferenceinaninterestrateswaprelationship_4e8a3fc7-ca51-4737-95c6-c33918eed3b8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtConversionConvertedInstrumentAmount1_e1223600-7d4d-4dd6-a9f9-1ea1d58ed44e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtConversionConvertedInstrumentAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_47f20138-adfc-4ba1-9412-716b81278359" xlink:to="loc_us-gaap_DebtConversionConvertedInstrumentAmount1_e1223600-7d4d-4dd6-a9f9-1ea1d58ed44e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_32814185-8b84-4eb7-a41c-49e126670946" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_47f20138-adfc-4ba1-9412-716b81278359" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_32814185-8b84-4eb7-a41c-49e126670946" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_DebtExchangeAdditionalCashConsideration_6b86dc45-fda8-4200-b10d-1fdf519e7f19" xlink:href="amgn-20201231.xsd#amgn_DebtExchangeAdditionalCashConsideration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_47f20138-adfc-4ba1-9412-716b81278359" xlink:to="loc_amgn_DebtExchangeAdditionalCashConsideration_6b86dc45-fda8-4200-b10d-1fdf519e7f19" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscount_e21c1862-5ff9-49f0-99fb-b8e5ae4e6c04" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_47f20138-adfc-4ba1-9412-716b81278359" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscount_e21c1862-5ff9-49f0-99fb-b8e5ae4e6c04" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_ddee79e8-f78c-4f1e-8d5d-be6aa1792ed9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_47f20138-adfc-4ba1-9412-716b81278359" xlink:to="loc_us-gaap_DebtInstrumentTable_ddee79e8-f78c-4f1e-8d5d-be6aa1792ed9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_e4925be2-8c02-47f3-9b87-e0d1e5b098ab" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_ddee79e8-f78c-4f1e-8d5d-be6aa1792ed9" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_e4925be2-8c02-47f3-9b87-e0d1e5b098ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_e4925be2-8c02-47f3-9b87-e0d1e5b098ab_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_e4925be2-8c02-47f3-9b87-e0d1e5b098ab" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_e4925be2-8c02-47f3-9b87-e0d1e5b098ab_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_b294c0e1-a5c2-457e-8b98-59a47394fe73" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_e4925be2-8c02-47f3-9b87-e0d1e5b098ab" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_b294c0e1-a5c2-457e-8b98-59a47394fe73" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableOtherPayablesMember_25cf9777-04b5-4cef-978a-233701bb7564" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesPayableOtherPayablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_b294c0e1-a5c2-457e-8b98-59a47394fe73" xlink:to="loc_us-gaap_NotesPayableOtherPayablesMember_25cf9777-04b5-4cef-978a-233701bb7564" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableToBanksMember_1682a4e8-43f3-4659-95df-588db8be8b6e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesPayableToBanksMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_b294c0e1-a5c2-457e-8b98-59a47394fe73" xlink:to="loc_us-gaap_NotesPayableToBanksMember_1682a4e8-43f3-4659-95df-588db8be8b6e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_30b386da-d231-411a-8768-7994d189fb30" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_ddee79e8-f78c-4f1e-8d5d-be6aa1792ed9" xlink:to="loc_us-gaap_DebtInstrumentAxis_30b386da-d231-411a-8768-7994d189fb30" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_30b386da-d231-411a-8768-7994d189fb30_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_30b386da-d231-411a-8768-7994d189fb30" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_30b386da-d231-411a-8768-7994d189fb30_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_30b386da-d231-411a-8768-7994d189fb30" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointTwoZeroPercentNotesDue2019Member_f4d736cf-4e0b-4d4f-8409-ac6ff6afad7f" xlink:href="amgn-20201231.xsd#amgn_TwoPointTwoZeroPercentNotesDue2019Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_TwoPointTwoZeroPercentNotesDue2019Member_f4d736cf-4e0b-4d4f-8409-ac6ff6afad7f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ThreePointFourFivePercentNotesDue2020Member_e25309aa-6b59-42cf-aafa-6c455fa766e7" xlink:href="amgn-20201231.xsd#amgn_ThreePointFourFivePercentNotesDue2020Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_ThreePointFourFivePercentNotesDue2020Member_e25309aa-6b59-42cf-aafa-6c455fa766e7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FourPointOneZeroPercentNotesDue2021Member_3d3ac13c-a2fa-42b9-bc90-d2ed60ae850a" xlink:href="amgn-20201231.xsd#amgn_FourPointOneZeroPercentNotesDue2021Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_FourPointOneZeroPercentNotesDue2021Member_3d3ac13c-a2fa-42b9-bc90-d2ed60ae850a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ThreePointEightSevenFivePercentNotesDue2021Member_c04dcda4-123e-4599-aeb1-73318f43413e" xlink:href="amgn-20201231.xsd#amgn_ThreePointEightSevenFivePercentNotesDue2021Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_ThreePointEightSevenFivePercentNotesDue2021Member_c04dcda4-123e-4599-aeb1-73318f43413e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ThreePointSixTwoFivePercentNotesDue2022Member_62fac120-3072-4bab-a635-39a35235cd89" xlink:href="amgn-20201231.xsd#amgn_ThreePointSixTwoFivePercentNotesDue2022Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_ThreePointSixTwoFivePercentNotesDue2022Member_62fac120-3072-4bab-a635-39a35235cd89" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ThreePointSixTwoFivePercentNotesDue2024Member_cfafd3e1-ccb1-49d1-a996-783b78a34d0f" xlink:href="amgn-20201231.xsd#amgn_ThreePointSixTwoFivePercentNotesDue2024Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_ThreePointSixTwoFivePercentNotesDue2024Member_cfafd3e1-ccb1-49d1-a996-783b78a34d0f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ThreePointOneTwoFivePercentNotesDueTwoZeroTwoFiveMember_b35abaf3-9e3e-4826-819a-7052f4607256" xlink:href="amgn-20201231.xsd#amgn_ThreePointOneTwoFivePercentNotesDueTwoZeroTwoFiveMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_ThreePointOneTwoFivePercentNotesDueTwoZeroTwoFiveMember_b35abaf3-9e3e-4826-819a-7052f4607256" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointSixZeroNotesDueTwoZeroTwoSixMember_a72bc91a-3678-4875-8368-4392d2ed3b34" xlink:href="amgn-20201231.xsd#amgn_TwoPointSixZeroNotesDueTwoZeroTwoSixMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_TwoPointSixZeroNotesDueTwoZeroTwoSixMember_a72bc91a-3678-4875-8368-4392d2ed3b34" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_OnePointTwoFivePercentEuroNotesdueTwoZeroTwoTwoMember_d1361ac4-1577-4a08-8932-2bc2c53d8869" xlink:href="amgn-20201231.xsd#amgn_OnePointTwoFivePercentEuroNotesdueTwoZeroTwoTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_OnePointTwoFivePercentEuroNotesdueTwoZeroTwoTwoMember_d1361ac4-1577-4a08-8932-2bc2c53d8869" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ZeroPointFortyOnePercentSwissFrancBondsDueTwoThousandTwentyThreeMember_7dfd8d76-81af-4ef6-9206-58677dbd750b" xlink:href="amgn-20201231.xsd#amgn_ZeroPointFortyOnePercentSwissFrancBondsDueTwoThousandTwentyThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_ZeroPointFortyOnePercentSwissFrancBondsDueTwoThousandTwentyThreeMember_7dfd8d76-81af-4ef6-9206-58677dbd750b" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPercentEuroNotesDueTwoThousandTwentySixMember_06215934-7184-4bef-b65b-9976bbfc9f7f" xlink:href="amgn-20201231.xsd#amgn_TwoPercentEuroNotesDueTwoThousandTwentySixMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_TwoPercentEuroNotesDueTwoThousandTwentySixMember_06215934-7184-4bef-b65b-9976bbfc9f7f" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FivePointFiveZeroPercentPoundSterlingNotesDue2026Member_0140a8f7-001e-4f0f-ad4e-c80e2f8a9015" xlink:href="amgn-20201231.xsd#amgn_FivePointFiveZeroPercentPoundSterlingNotesDue2026Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_FivePointFiveZeroPercentPoundSterlingNotesDue2026Member_0140a8f7-001e-4f0f-ad4e-c80e2f8a9015" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FourPercentPoundSterlingNotesDue2029Member_facf3224-7b39-4598-a6f3-386a978b42eb" xlink:href="amgn-20201231.xsd#amgn_FourPercentPoundSterlingNotesDue2029Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_FourPercentPoundSterlingNotesDue2029Member_facf3224-7b39-4598-a6f3-386a978b42eb" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FourPointSixSixThreePercentNotesDueTwoZeroFiveOneMember_3d70cef5-ef43-4a91-b122-074de5454b13" xlink:href="amgn-20201231.xsd#amgn_FourPointSixSixThreePercentNotesDueTwoZeroFiveOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_FourPointSixSixThreePercentNotesDueTwoZeroFiveOneMember_3d70cef5-ef43-4a91-b122-074de5454b13" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_SixPointThreeSevenFivePercentNotesDue2037Member_dde10b53-26bb-4b4d-84ea-ae002f938b46" xlink:href="amgn-20201231.xsd#amgn_SixPointThreeSevenFivePercentNotesDue2037Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_SixPointThreeSevenFivePercentNotesDue2037Member_dde10b53-26bb-4b4d-84ea-ae002f938b46" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointSevenSevenPercentNotesDueTwoZeroFiveThreeMember_f2c2d23e-040d-4716-844e-4a686bd051ef" xlink:href="amgn-20201231.xsd#amgn_TwoPointSevenSevenPercentNotesDueTwoZeroFiveThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_TwoPointSevenSevenPercentNotesDueTwoZeroFiveThreeMember_f2c2d23e-040d-4716-844e-4a686bd051ef" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_SixPointNineZeroPercentNotesDue2038Member_00a3dd17-61d1-4977-80ae-83fb9ccc0dd8" xlink:href="amgn-20201231.xsd#amgn_SixPointNineZeroPercentNotesDue2038Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_SixPointNineZeroPercentNotesDue2038Member_00a3dd17-61d1-4977-80ae-83fb9ccc0dd8" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_SixPointFourZeroPercentNotesDue2039Member_ba0c622b-5ab9-49d1-8c6d-d9652b6273ea" xlink:href="amgn-20201231.xsd#amgn_SixPointFourZeroPercentNotesDue2039Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_SixPointFourZeroPercentNotesDue2039Member_ba0c622b-5ab9-49d1-8c6d-d9652b6273ea" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FivePointSevenFivePercentNotesDue2040Member_ac381713-7544-4ca1-a88f-f2fd3f4fa2af" xlink:href="amgn-20201231.xsd#amgn_FivePointSevenFivePercentNotesDue2040Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_FivePointSevenFivePercentNotesDue2040Member_ac381713-7544-4ca1-a88f-f2fd3f4fa2af" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FivePointOneFivePercentNotesDue2041Member_b9538959-4af5-4fbe-8094-9109650fb081" xlink:href="amgn-20201231.xsd#amgn_FivePointOneFivePercentNotesDue2041Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_FivePointOneFivePercentNotesDue2041Member_b9538959-4af5-4fbe-8094-9109650fb081" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FivePointSixFivePercentNotesDue2042Member_8f6b84b8-27ad-4b31-9c60-e57de1857b23" xlink:href="amgn-20201231.xsd#amgn_FivePointSixFivePercentNotesDue2042Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_FivePointSixFivePercentNotesDue2042Member_8f6b84b8-27ad-4b31-9c60-e57de1857b23" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FivePointThreeSevenFivePercentNotesDue2043Member_1e31a48e-6535-4d98-9d36-e04efc48c993" xlink:href="amgn-20201231.xsd#amgn_FivePointThreeSevenFivePercentNotesDue2043Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bd8af0e8-5160-4927-8ab0-a6cff284e38d" xlink:to="loc_amgn_FivePointThreeSevenFivePercentNotesDue2043Member_1e31a48e-6535-4d98-9d36-e04efc48c993" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_bd09bc4e-2c61-416b-a638-3a40c82461bb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_ddee79e8-f78c-4f1e-8d5d-be6aa1792ed9" xlink:to="loc_us-gaap_VariableRateAxis_bd09bc4e-2c61-416b-a638-3a40c82461bb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_bd09bc4e-2c61-416b-a638-3a40c82461bb_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_bd09bc4e-2c61-416b-a638-3a40c82461bb" xlink:to="loc_us-gaap_VariableRateDomain_bd09bc4e-2c61-416b-a638-3a40c82461bb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_e42f3456-bc3e-45a7-8c88-cbb95cc45129" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_bd09bc4e-2c61-416b-a638-3a40c82461bb" xlink:to="loc_us-gaap_VariableRateDomain_e42f3456-bc3e-45a7-8c88-cbb95cc45129" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_cf6b57d4-7b34-4aea-9f64-af4449b11146" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_e42f3456-bc3e-45a7-8c88-cbb95cc45129" xlink:to="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_cf6b57d4-7b34-4aea-9f64-af4449b11146" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_InterestRateSwapAxis_1d09ff48-0cfe-404e-ada1-e51ca053db4c" xlink:href="amgn-20201231.xsd#amgn_InterestRateSwapAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_ddee79e8-f78c-4f1e-8d5d-be6aa1792ed9" xlink:to="loc_amgn_InterestRateSwapAxis_1d09ff48-0cfe-404e-ada1-e51ca053db4c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_InterestRateSwapDomain_1d09ff48-0cfe-404e-ada1-e51ca053db4c_default" xlink:href="amgn-20201231.xsd#amgn_InterestRateSwapDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_amgn_InterestRateSwapAxis_1d09ff48-0cfe-404e-ada1-e51ca053db4c" xlink:to="loc_amgn_InterestRateSwapDomain_1d09ff48-0cfe-404e-ada1-e51ca053db4c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_InterestRateSwapDomain_2ee81878-6988-4c83-8f7b-861edff5b9e3" xlink:href="amgn-20201231.xsd#amgn_InterestRateSwapDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_amgn_InterestRateSwapAxis_1d09ff48-0cfe-404e-ada1-e51ca053db4c" xlink:to="loc_amgn_InterestRateSwapDomain_2ee81878-6988-4c83-8f7b-861edff5b9e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_InterestRateSwapOneMember_7dfb10e3-bcbf-4a6f-9ff9-2f7a2abbe6c8" xlink:href="amgn-20201231.xsd#amgn_InterestRateSwapOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amgn_InterestRateSwapDomain_2ee81878-6988-4c83-8f7b-861edff5b9e3" xlink:to="loc_amgn_InterestRateSwapOneMember_7dfb10e3-bcbf-4a6f-9ff9-2f7a2abbe6c8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_InterestRateSwapTwoMember_5ca429c1-4f72-4a64-91dd-71da35c00be9" xlink:href="amgn-20201231.xsd#amgn_InterestRateSwapTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amgn_InterestRateSwapDomain_2ee81878-6988-4c83-8f7b-861edff5b9e3" xlink:to="loc_amgn_InterestRateSwapTwoMember_5ca429c1-4f72-4a64-91dd-71da35c00be9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_InterestRateSwapThreeMember_56a663ca-3874-4a0f-985c-0e1732785ecb" xlink:href="amgn-20201231.xsd#amgn_InterestRateSwapThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amgn_InterestRateSwapDomain_2ee81878-6988-4c83-8f7b-861edff5b9e3" xlink:to="loc_amgn_InterestRateSwapThreeMember_56a663ca-3874-4a0f-985c-0e1732785ecb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_ef38fc34-6e9a-4aa4-8eab-b5bd03ce659c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_ddee79e8-f78c-4f1e-8d5d-be6aa1792ed9" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_ef38fc34-6e9a-4aa4-8eab-b5bd03ce659c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_ef38fc34-6e9a-4aa4-8eab-b5bd03ce659c_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_ef38fc34-6e9a-4aa4-8eab-b5bd03ce659c" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_ef38fc34-6e9a-4aa4-8eab-b5bd03ce659c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_643eb017-f834-4c5b-865f-6d981ae6a632" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_ef38fc34-6e9a-4aa4-8eab-b5bd03ce659c" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_643eb017-f834-4c5b-865f-6d981ae6a632" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_8b869c97-3bbb-43f6-975f-f42cf0bb9df4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_643eb017-f834-4c5b-865f-6d981ae6a632" xlink:to="loc_us-gaap_InterestRateSwapMember_8b869c97-3bbb-43f6-975f-f42cf0bb9df4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_89674f38-ca2f-4dc1-adcc-2009b8fc7caa" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_ddee79e8-f78c-4f1e-8d5d-be6aa1792ed9" xlink:to="loc_us-gaap_HedgingDesignationAxis_89674f38-ca2f-4dc1-adcc-2009b8fc7caa" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_89674f38-ca2f-4dc1-adcc-2009b8fc7caa_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_89674f38-ca2f-4dc1-adcc-2009b8fc7caa" xlink:to="loc_us-gaap_HedgingDesignationDomain_89674f38-ca2f-4dc1-adcc-2009b8fc7caa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_109efc7b-ac42-4a02-9c61-d66cb3d21af9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_89674f38-ca2f-4dc1-adcc-2009b8fc7caa" xlink:to="loc_us-gaap_HedgingDesignationDomain_109efc7b-ac42-4a02-9c61-d66cb3d21af9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_7e1b3b2b-ed61-4cb9-8ed9-01fdfdd92e7a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_109efc7b-ac42-4a02-9c61-d66cb3d21af9" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_7e1b3b2b-ed61-4cb9-8ed9-01fdfdd92e7a" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/FinancingarrangementsShelfRegistrationStatementsandOtherFacilitiesDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#FinancingarrangementsShelfRegistrationStatementsandOtherFacilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/FinancingarrangementsShelfRegistrationStatementsandOtherFacilitiesDetails" xlink:type="extended" id="i8f89aab99b7846709d01eea20dff9276_FinancingarrangementsShelfRegistrationStatementsandOtherFacilitiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_afeacc57-2013-4923-9ec4-e8b3d71c2ca7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_6f15526d-0f06-4b35-8ede-28e2a9257fb7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_afeacc57-2013-4923-9ec4-e8b3d71c2ca7" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_6f15526d-0f06-4b35-8ede-28e2a9257fb7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_AmountByWhichBorrowingCapacityUnderSyndicatedUnsecuredRevolvingCreditAgreementMayBeIncreasedUponOurRequestAtDiscretionOfBanks_6e2c7495-cb48-442b-b726-3fa4a2b7ded3" xlink:href="amgn-20201231.xsd#amgn_AmountByWhichBorrowingCapacityUnderSyndicatedUnsecuredRevolvingCreditAgreementMayBeIncreasedUponOurRequestAtDiscretionOfBanks"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_afeacc57-2013-4923-9ec4-e8b3d71c2ca7" xlink:to="loc_amgn_AmountByWhichBorrowingCapacityUnderSyndicatedUnsecuredRevolvingCreditAgreementMayBeIncreasedUponOurRequestAtDiscretionOfBanks_6e2c7495-cb48-442b-b726-3fa4a2b7ded3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_LineOfCreditFacilityInitialCommitmentTerm_c45c685d-0dba-450e-9cdf-6f9f5010e7d7" xlink:href="amgn-20201231.xsd#amgn_LineOfCreditFacilityInitialCommitmentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_afeacc57-2013-4923-9ec4-e8b3d71c2ca7" xlink:to="loc_amgn_LineOfCreditFacilityInitialCommitmentTerm_c45c685d-0dba-450e-9cdf-6f9f5010e7d7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_LineofCreditFacilityNumberOfRenewalOptions_99332b12-5bfd-4d04-bbc6-678053b11868" xlink:href="amgn-20201231.xsd#amgn_LineofCreditFacilityNumberOfRenewalOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_afeacc57-2013-4923-9ec4-e8b3d71c2ca7" xlink:to="loc_amgn_LineofCreditFacilityNumberOfRenewalOptions_99332b12-5bfd-4d04-bbc6-678053b11868" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_LineOfCreditFacilityExtensionOfCommitmentTerm_1a40b349-7cd1-4c8e-9bc3-434592f83621" xlink:href="amgn-20201231.xsd#amgn_LineOfCreditFacilityExtensionOfCommitmentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_afeacc57-2013-4923-9ec4-e8b3d71c2ca7" xlink:to="loc_amgn_LineOfCreditFacilityExtensionOfCommitmentTerm_1a40b349-7cd1-4c8e-9bc3-434592f83621" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_f9ec6555-09a5-4ba9-91ba-84933687405a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_afeacc57-2013-4923-9ec4-e8b3d71c2ca7" xlink:to="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_f9ec6555-09a5-4ba9-91ba-84933687405a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_a6e89d13-a83a-4843-9838-94fde715f03e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_afeacc57-2013-4923-9ec4-e8b3d71c2ca7" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_a6e89d13-a83a-4843-9838-94fde715f03e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_925986e7-83e3-4540-9d68-15861229d55a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentDescriptionOfVariableRateBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_afeacc57-2013-4923-9ec4-e8b3d71c2ca7" xlink:to="loc_us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_925986e7-83e3-4540-9d68-15861229d55a" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit_7f224415-3aaa-4cb0-88a5-a0db04d82f71" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_afeacc57-2013-4923-9ec4-e8b3d71c2ca7" xlink:to="loc_us-gaap_LineOfCredit_7f224415-3aaa-4cb0-88a5-a0db04d82f71" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_f4c32b6c-57cf-43e1-aa9c-06ffe65395ae" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_afeacc57-2013-4923-9ec4-e8b3d71c2ca7" xlink:to="loc_us-gaap_DebtInstrumentTable_f4c32b6c-57cf-43e1-aa9c-06ffe65395ae" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_1873d351-fae2-47ae-a135-0400e7171349" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_f4c32b6c-57cf-43e1-aa9c-06ffe65395ae" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_1873d351-fae2-47ae-a135-0400e7171349" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_1873d351-fae2-47ae-a135-0400e7171349_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_1873d351-fae2-47ae-a135-0400e7171349" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_1873d351-fae2-47ae-a135-0400e7171349_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_68cc0c2f-10f5-436d-9739-80773b9d4b9e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_1873d351-fae2-47ae-a135-0400e7171349" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_68cc0c2f-10f5-436d-9739-80773b9d4b9e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_8fcd5822-2ac4-4673-a6df-a0aa6045f84f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_68cc0c2f-10f5-436d-9739-80773b9d4b9e" xlink:to="loc_us-gaap_LineOfCreditMember_8fcd5822-2ac4-4673-a6df-a0aa6045f84f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_77a03e09-be1d-4c99-9060-7e45d2596afb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_f4c32b6c-57cf-43e1-aa9c-06ffe65395ae" xlink:to="loc_us-gaap_VariableRateAxis_77a03e09-be1d-4c99-9060-7e45d2596afb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_77a03e09-be1d-4c99-9060-7e45d2596afb_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_77a03e09-be1d-4c99-9060-7e45d2596afb" xlink:to="loc_us-gaap_VariableRateDomain_77a03e09-be1d-4c99-9060-7e45d2596afb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_21307837-b51a-43d2-a3ec-03eeca7835cb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_77a03e09-be1d-4c99-9060-7e45d2596afb" xlink:to="loc_us-gaap_VariableRateDomain_21307837-b51a-43d2-a3ec-03eeca7835cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalFundsEffectiveSwapRateMember_4bf5494d-8055-4e7f-8556-39fcaf53a614" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FederalFundsEffectiveSwapRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_21307837-b51a-43d2-a3ec-03eeca7835cb" xlink:to="loc_us-gaap_FederalFundsEffectiveSwapRateMember_4bf5494d-8055-4e7f-8556-39fcaf53a614" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_da07869b-099f-474b-a11c-28f44c5ab463" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_21307837-b51a-43d2-a3ec-03eeca7835cb" xlink:to="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_da07869b-099f-474b-a11c-28f44c5ab463" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/FinancingarrangementsContractualMaturitiesofLongtermDebtDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#FinancingarrangementsContractualMaturitiesofLongtermDebtDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/FinancingarrangementsContractualMaturitiesofLongtermDebtDetails" xlink:type="extended" id="i76f7b7c979884c6cb30c4f07f56bfe4b_FinancingarrangementsContractualMaturitiesofLongtermDebtDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/FinancingarrangementsInterestCostsDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#FinancingarrangementsInterestCostsDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/FinancingarrangementsInterestCostsDetails" xlink:type="extended" id="i9e70edeaecf94d179e7ec4bb0815c2cb_FinancingarrangementsInterestCostsDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/Stockholdersequity" xlink:type="simple" xlink:href="amgn-20201231.xsd#Stockholdersequity"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/Stockholdersequity" xlink:type="extended" id="ifa957657e5ca4c9398c8dcc2a5c96a72_Stockholdersequity"/>
  <link:roleRef roleURI="http://www.amgen.com/role/StockholdersequityTables" xlink:type="simple" xlink:href="amgn-20201231.xsd#StockholdersequityTables"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/StockholdersequityTables" xlink:type="extended" id="ie5128c1cbf0149c7a686f81506336901_StockholdersequityTables"/>
  <link:roleRef roleURI="http://www.amgen.com/role/StockholdersequityStockRepurchaseProgramDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#StockholdersequityStockRepurchaseProgramDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/StockholdersequityStockRepurchaseProgramDetails" xlink:type="extended" id="i8e517afbce8d4acc98da663b9357b8cd_StockholdersequityStockRepurchaseProgramDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/StockholdersequityDividendsDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#StockholdersequityDividendsDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/StockholdersequityDividendsDetails" xlink:type="extended" id="ic55d8b8a8fcc4bbc9a75233e5aec58be_StockholdersequityDividendsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_dde8719d-67f0-4be6-88c6-b9785f337392" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockDividendsPerShareDeclared_52665624-0591-4d24-a620-74b04d944629" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockDividendsPerShareDeclared"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_dde8719d-67f0-4be6-88c6-b9785f337392" xlink:to="loc_us-gaap_CommonStockDividendsPerShareDeclared_52665624-0591-4d24-a620-74b04d944629" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockDividendsPerShareCashPaid_86308a94-f8ff-410f-80e5-85890a85c6bb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockDividendsPerShareCashPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_dde8719d-67f0-4be6-88c6-b9785f337392" xlink:to="loc_us-gaap_CommonStockDividendsPerShareCashPaid_86308a94-f8ff-410f-80e5-85890a85c6bb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_8073fa5e-d5c7-43d5-9d97-60a83ae58f7f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_dde8719d-67f0-4be6-88c6-b9785f337392" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_8073fa5e-d5c7-43d5-9d97-60a83ae58f7f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementScenarioAxis_fa3a5212-fb54-4380-b85a-caf505a32e3a" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementScenarioAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_8073fa5e-d5c7-43d5-9d97-60a83ae58f7f" xlink:to="loc_srt_StatementScenarioAxis_fa3a5212-fb54-4380-b85a-caf505a32e3a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_fa3a5212-fb54-4380-b85a-caf505a32e3a_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementScenarioAxis_fa3a5212-fb54-4380-b85a-caf505a32e3a" xlink:to="loc_srt_ScenarioUnspecifiedDomain_fa3a5212-fb54-4380-b85a-caf505a32e3a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_ca69937f-d3b9-4b0d-bc36-75f8bf88ac34" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementScenarioAxis_fa3a5212-fb54-4380-b85a-caf505a32e3a" xlink:to="loc_srt_ScenarioUnspecifiedDomain_ca69937f-d3b9-4b0d-bc36-75f8bf88ac34" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioForecastMember_1259fc3f-690d-4b6d-bc49-ec0f09c2b4cd" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioForecastMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_ca69937f-d3b9-4b0d-bc36-75f8bf88ac34" xlink:to="loc_srt_ScenarioForecastMember_1259fc3f-690d-4b6d-bc49-ec0f09c2b4cd" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/StockholdersequityComponentsofAOCIDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#StockholdersequityComponentsofAOCIDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/StockholdersequityComponentsofAOCIDetails" xlink:type="extended" id="i1cef94e3fd6742fe9bfcdc70e93d5cd3_StockholdersequityComponentsofAOCIDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_14a89e73-376c-4972-95ec-6e4a969e37ae" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_b3d7def2-b993-46fd-9e9a-c293dd56a162" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_14a89e73-376c-4972-95ec-6e4a969e37ae" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_b3d7def2-b993-46fd-9e9a-c293dd56a162" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_7979b9d9-21aa-4e0d-b6b7-b42c56c15b85" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_b3d7def2-b993-46fd-9e9a-c293dd56a162" xlink:to="loc_us-gaap_StockholdersEquity_7979b9d9-21aa-4e0d-b6b7-b42c56c15b85" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_8105f1cd-00e9-49f3-888e-740b04bd84e6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_b3d7def2-b993-46fd-9e9a-c293dd56a162" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_8105f1cd-00e9-49f3-888e-740b04bd84e6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OciBeforeReclassificationsBeforeTaxAttributableToParent_bb667587-a2c8-41fd-8324-44b5216fdd58" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OciBeforeReclassificationsBeforeTaxAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_b3d7def2-b993-46fd-9e9a-c293dd56a162" xlink:to="loc_us-gaap_OciBeforeReclassificationsBeforeTaxAttributableToParent_bb667587-a2c8-41fd-8324-44b5216fdd58" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAociCurrentPeriodBeforeTaxAttributableToParent_9a3fdef0-464c-46a4-bd11-56517c530b61" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationFromAociCurrentPeriodBeforeTaxAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_b3d7def2-b993-46fd-9e9a-c293dd56a162" xlink:to="loc_us-gaap_ReclassificationFromAociCurrentPeriodBeforeTaxAttributableToParent_9a3fdef0-464c-46a4-bd11-56517c530b61" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_OtherComprehensiveIncomeLossOtherAdjustmentbeforeTax_d4338aff-47ee-46aa-9083-84b594952d17" xlink:href="amgn-20201231.xsd#amgn_OtherComprehensiveIncomeLossOtherAdjustmentbeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_b3d7def2-b993-46fd-9e9a-c293dd56a162" xlink:to="loc_amgn_OtherComprehensiveIncomeLossOtherAdjustmentbeforeTax_d4338aff-47ee-46aa-9083-84b594952d17" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_258eb415-aecf-404d-9c97-310434848405" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_b3d7def2-b993-46fd-9e9a-c293dd56a162" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_258eb415-aecf-404d-9c97-310434848405" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_396ba300-59ee-430b-bdb7-eacff8f4b22a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_ec9d4aa1-8652-48f8-8047-58a8e3530e38" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_14a89e73-376c-4972-95ec-6e4a969e37ae" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_ec9d4aa1-8652-48f8-8047-58a8e3530e38" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_d8681696-c35b-45c1-b372-677a0fac15e5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_ec9d4aa1-8652-48f8-8047-58a8e3530e38" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_d8681696-c35b-45c1-b372-677a0fac15e5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_d8681696-c35b-45c1-b372-677a0fac15e5_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_d8681696-c35b-45c1-b372-677a0fac15e5" xlink:to="loc_us-gaap_EquityComponentDomain_d8681696-c35b-45c1-b372-677a0fac15e5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_133a1a04-af65-4976-9486-30cbacfc2ef7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_d8681696-c35b-45c1-b372-677a0fac15e5" xlink:to="loc_us-gaap_EquityComponentDomain_133a1a04-af65-4976-9486-30cbacfc2ef7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_fe96a858-281a-4f41-b003-87b4bb1fc625" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedTranslationAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_133a1a04-af65-4976-9486-30cbacfc2ef7" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_fe96a858-281a-4f41-b003-87b4bb1fc625" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_ec572665-a4e8-4692-8f9c-6352d5197da0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_133a1a04-af65-4976-9486-30cbacfc2ef7" xlink:to="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_ec572665-a4e8-4692-8f9c-6352d5197da0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_c4df6ddd-48b2-4d19-8229-5c0c22b4c480" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_133a1a04-af65-4976-9486-30cbacfc2ef7" xlink:to="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_c4df6ddd-48b2-4d19-8229-5c0c22b4c480" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_AccumulatedOtherAdjustmentAttributabletoParentMember_09a32e81-4419-453b-9202-9aa6456f0ee9" xlink:href="amgn-20201231.xsd#amgn_AccumulatedOtherAdjustmentAttributabletoParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_133a1a04-af65-4976-9486-30cbacfc2ef7" xlink:to="loc_amgn_AccumulatedOtherAdjustmentAttributabletoParentMember_09a32e81-4419-453b-9202-9aa6456f0ee9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_d416f9d2-80f5-452c-928b-adea3111ff42" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_133a1a04-af65-4976-9486-30cbacfc2ef7" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_d416f9d2-80f5-452c-928b-adea3111ff42" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_140052ea-6763-474f-a430-25bbef8bad5d" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_ec9d4aa1-8652-48f8-8047-58a8e3530e38" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_140052ea-6763-474f-a430-25bbef8bad5d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_140052ea-6763-474f-a430-25bbef8bad5d_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_140052ea-6763-474f-a430-25bbef8bad5d" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_140052ea-6763-474f-a430-25bbef8bad5d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_f18fb4bd-3a5c-4c72-88d6-c5b17fcfb8db" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_140052ea-6763-474f-a430-25bbef8bad5d" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_f18fb4bd-3a5c-4c72-88d6-c5b17fcfb8db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_7fba6a9d-7fc0-43c8-b552-fb8ca1b8318d" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_f18fb4bd-3a5c-4c72-88d6-c5b17fcfb8db" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_7fba6a9d-7fc0-43c8-b552-fb8ca1b8318d" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/StockholdersequityAccumulatedOtherComprehensiveIncomeLossTextualDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#StockholdersequityAccumulatedOtherComprehensiveIncomeLossTextualDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/StockholdersequityAccumulatedOtherComprehensiveIncomeLossTextualDetails" xlink:type="extended" id="ie817923a04954f5c9f8b9e1483bb84ec_StockholdersequityAccumulatedOtherComprehensiveIncomeLossTextualDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/StockholdersequityReclassificationsoutofAOCIDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#StockholdersequityReclassificationsoutofAOCIDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/StockholdersequityReclassificationsoutofAOCIDetails" xlink:type="extended" id="i74946431775e4e93828ba880036dbab7_StockholdersequityReclassificationsoutofAOCIDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_7efbce62-10ab-424c-8295-800467deb4c8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_7d53c4f7-f060-46a2-8d66-5528a34cc5a5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_7efbce62-10ab-424c-8295-800467deb4c8" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_7d53c4f7-f060-46a2-8d66-5528a34cc5a5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_4952c378-9260-4b6b-ad7a-5129649847e4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_7efbce62-10ab-424c-8295-800467deb4c8" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_4952c378-9260-4b6b-ad7a-5129649847e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebt_8e17fedd-f57b-4964-89ed-c5c3c32e8828" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_7efbce62-10ab-424c-8295-800467deb4c8" xlink:to="loc_us-gaap_InterestExpenseDebt_8e17fedd-f57b-4964-89ed-c5c3c32e8828" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_f992d7b2-68e0-4763-8747-cb8a4e3f745a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_7efbce62-10ab-424c-8295-800467deb4c8" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_f992d7b2-68e0-4763-8747-cb8a4e3f745a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_1031d01c-a997-4fb3-bee6-58c9edd07d71" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_7efbce62-10ab-424c-8295-800467deb4c8" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_1031d01c-a997-4fb3-bee6-58c9edd07d71" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_f693644f-bf18-41a0-af78-e96c62ac6959" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_7efbce62-10ab-424c-8295-800467deb4c8" xlink:to="loc_us-gaap_NetIncomeLoss_f693644f-bf18-41a0-af78-e96c62ac6959" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_4fc6252c-3103-4cd5-8d94-93db3080660f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_7efbce62-10ab-424c-8295-800467deb4c8" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_4fc6252c-3103-4cd5-8d94-93db3080660f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_8144d5af-8012-4e2a-8dd3-46fe08a3b45e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_4fc6252c-3103-4cd5-8d94-93db3080660f" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_8144d5af-8012-4e2a-8dd3-46fe08a3b45e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_8144d5af-8012-4e2a-8dd3-46fe08a3b45e_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_8144d5af-8012-4e2a-8dd3-46fe08a3b45e" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_8144d5af-8012-4e2a-8dd3-46fe08a3b45e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_0699f699-1297-4448-b420-409815a083d6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_8144d5af-8012-4e2a-8dd3-46fe08a3b45e" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_0699f699-1297-4448-b420-409815a083d6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_54338ad3-650c-46aa-b49d-c0d20f4bf998" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_0699f699-1297-4448-b420-409815a083d6" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_54338ad3-650c-46aa-b49d-c0d20f4bf998" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_4f0c6562-1fab-4b98-afbe-53be607764c9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_4fc6252c-3103-4cd5-8d94-93db3080660f" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_4f0c6562-1fab-4b98-afbe-53be607764c9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_4f0c6562-1fab-4b98-afbe-53be607764c9_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_4f0c6562-1fab-4b98-afbe-53be607764c9" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_4f0c6562-1fab-4b98-afbe-53be607764c9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_bf7377c7-a5d4-483b-b673-9fad70e8b59f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_4f0c6562-1fab-4b98-afbe-53be607764c9" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_bf7377c7-a5d4-483b-b673-9fad70e8b59f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeContractMember_0956d98f-1a79-4899-b1a4-16eb8ab061f2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ForeignExchangeContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_bf7377c7-a5d4-483b-b673-9fad70e8b59f" xlink:to="loc_us-gaap_ForeignExchangeContractMember_0956d98f-1a79-4899-b1a4-16eb8ab061f2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CrossCurrencySwapContractsMember_f75eb8fa-d0b3-4590-8180-be410333277b" xlink:href="amgn-20201231.xsd#amgn_CrossCurrencySwapContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_bf7377c7-a5d4-483b-b673-9fad70e8b59f" xlink:to="loc_amgn_CrossCurrencySwapContractsMember_f75eb8fa-d0b3-4590-8180-be410333277b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ForwardInterestRateContractMember_8ee41b7a-dc14-4214-b450-0e43ee926dc2" xlink:href="amgn-20201231.xsd#amgn_ForwardInterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_bf7377c7-a5d4-483b-b673-9fad70e8b59f" xlink:to="loc_amgn_ForwardInterestRateContractMember_8ee41b7a-dc14-4214-b450-0e43ee926dc2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_2247dc76-0444-444a-822c-b372dc13b161" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_4fc6252c-3103-4cd5-8d94-93db3080660f" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_2247dc76-0444-444a-822c-b372dc13b161" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_2247dc76-0444-444a-822c-b372dc13b161_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_2247dc76-0444-444a-822c-b372dc13b161" xlink:to="loc_us-gaap_HedgingRelationshipDomain_2247dc76-0444-444a-822c-b372dc13b161_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_9827bf66-c858-4416-9387-f581a4fa87ca" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_2247dc76-0444-444a-822c-b372dc13b161" xlink:to="loc_us-gaap_HedgingRelationshipDomain_9827bf66-c858-4416-9387-f581a4fa87ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgingMember_18242cd5-4dd5-46d7-96a2-5f64da4125f8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashFlowHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_9827bf66-c858-4416-9387-f581a4fa87ca" xlink:to="loc_us-gaap_CashFlowHedgingMember_18242cd5-4dd5-46d7-96a2-5f64da4125f8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_b1f15527-1ae6-42c8-b6f4-7e440ba66b7c" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_4fc6252c-3103-4cd5-8d94-93db3080660f" xlink:to="loc_srt_ProductOrServiceAxis_b1f15527-1ae6-42c8-b6f4-7e440ba66b7c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_b1f15527-1ae6-42c8-b6f4-7e440ba66b7c_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_b1f15527-1ae6-42c8-b6f4-7e440ba66b7c" xlink:to="loc_srt_ProductsAndServicesDomain_b1f15527-1ae6-42c8-b6f4-7e440ba66b7c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_ce6f3094-7633-49fd-abd1-6de0311dc8a1" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_b1f15527-1ae6-42c8-b6f4-7e440ba66b7c" xlink:to="loc_srt_ProductsAndServicesDomain_ce6f3094-7633-49fd-abd1-6de0311dc8a1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductMember_0f8f1528-b72e-4688-a72e-eb7f5fb110da" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_ce6f3094-7633-49fd-abd1-6de0311dc8a1" xlink:to="loc_us-gaap_ProductMember_0f8f1528-b72e-4688-a72e-eb7f5fb110da" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_6d93e214-b051-49b6-9eb7-5ee5ff192feb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_4fc6252c-3103-4cd5-8d94-93db3080660f" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_6d93e214-b051-49b6-9eb7-5ee5ff192feb" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_6d93e214-b051-49b6-9eb7-5ee5ff192feb_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_6d93e214-b051-49b6-9eb7-5ee5ff192feb" xlink:to="loc_us-gaap_EquityComponentDomain_6d93e214-b051-49b6-9eb7-5ee5ff192feb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_0ac17e19-5536-4e04-ba3d-8f49dc1d5c5e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_6d93e214-b051-49b6-9eb7-5ee5ff192feb" xlink:to="loc_us-gaap_EquityComponentDomain_0ac17e19-5536-4e04-ba3d-8f49dc1d5c5e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_c7252605-c27f-4eb7-be6c-296274695336" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_0ac17e19-5536-4e04-ba3d-8f49dc1d5c5e" xlink:to="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_c7252605-c27f-4eb7-be6c-296274695336" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_162ecfe5-7db6-4f5b-a6d9-8538c17213c5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_0ac17e19-5536-4e04-ba3d-8f49dc1d5c5e" xlink:to="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_162ecfe5-7db6-4f5b-a6d9-8538c17213c5" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/StockholdersequityOtherDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#StockholdersequityOtherDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/StockholdersequityOtherDetails" xlink:type="extended" id="i730972b1ce1e4f3899bc1b10cfdf026d_StockholdersequityOtherDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/Fairvaluemeasurement" xlink:type="simple" xlink:href="amgn-20201231.xsd#Fairvaluemeasurement"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/Fairvaluemeasurement" xlink:type="extended" id="i20dfb8f599f94f9c8e6da2f1e2f12a44_Fairvaluemeasurement"/>
  <link:roleRef roleURI="http://www.amgen.com/role/FairvaluemeasurementTables" xlink:type="simple" xlink:href="amgn-20201231.xsd#FairvaluemeasurementTables"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/FairvaluemeasurementTables" xlink:type="extended" id="i3390a51a6bd0440197051e7e96633459_FairvaluemeasurementTables"/>
  <link:roleRef roleURI="http://www.amgen.com/role/FairvaluemeasurementFairValueofFinancialAssetsandLiabilitiesonRecurringBasisDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#FairvaluemeasurementFairValueofFinancialAssetsandLiabilitiesonRecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/FairvaluemeasurementFairValueofFinancialAssetsandLiabilitiesonRecurringBasisDetails" xlink:type="extended" id="id4744eba16404bcc87d847c10085d7af_FairvaluemeasurementFairValueofFinancialAssetsandLiabilitiesonRecurringBasisDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_582e1e89-f983-409b-8ff0-a3e51a6cb5f7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosureAbstract_3904d52d-79bc-4341-9a83-0ff01dd900b4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_582e1e89-f983-409b-8ff0-a3e51a6cb5f7" xlink:to="loc_us-gaap_AssetsFairValueDisclosureAbstract_3904d52d-79bc-4341-9a83-0ff01dd900b4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_e16c13bf-b304-44b9-89dd-7f0cbe9b0d9d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_3904d52d-79bc-4341-9a83-0ff01dd900b4" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_e16c13bf-b304-44b9-89dd-7f0cbe9b0d9d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNi_0b2ce186-c155-4d5e-bfa9-027824787381" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquitySecuritiesFvNi"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_3904d52d-79bc-4341-9a83-0ff01dd900b4" xlink:to="loc_us-gaap_EquitySecuritiesFvNi_0b2ce186-c155-4d5e-bfa9-027824787381" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_DerivativeAssetsFairValueDisclosureAbstract_87de3cc6-bc1e-43a0-ab45-db1c2716a53a" xlink:href="amgn-20201231.xsd#amgn_DerivativeAssetsFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_3904d52d-79bc-4341-9a83-0ff01dd900b4" xlink:to="loc_amgn_DerivativeAssetsFairValueDisclosureAbstract_87de3cc6-bc1e-43a0-ab45-db1c2716a53a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCurrencyContractAssetFairValueDisclosure_8db87b38-431c-49a9-b58c-64ee176f8f8e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ForeignCurrencyContractAssetFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amgn_DerivativeAssetsFairValueDisclosureAbstract_87de3cc6-bc1e-43a0-ab45-db1c2716a53a" xlink:to="loc_us-gaap_ForeignCurrencyContractAssetFairValueDisclosure_8db87b38-431c-49a9-b58c-64ee176f8f8e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateFairValueHedgeAssetAtFairValue_bd69f29c-14b1-42f1-93c0-fb6fdc64ab94" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestRateFairValueHedgeAssetAtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amgn_DerivativeAssetsFairValueDisclosureAbstract_87de3cc6-bc1e-43a0-ab45-db1c2716a53a" xlink:to="loc_us-gaap_InterestRateFairValueHedgeAssetAtFairValue_bd69f29c-14b1-42f1-93c0-fb6fdc64ab94" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_1e62135c-f9ac-4c9e-9ffc-e826f937b8cd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_3904d52d-79bc-4341-9a83-0ff01dd900b4" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_1e62135c-f9ac-4c9e-9ffc-e826f937b8cd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_0430c5a9-f0d8-42bf-b2b9-693a2d793da2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_582e1e89-f983-409b-8ff0-a3e51a6cb5f7" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_0430c5a9-f0d8-42bf-b2b9-693a2d793da2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_DerivativeFinancialInstrumentsLiabilitiesFairValueDisclosureAbstract_9341a38f-af1b-40f7-b09d-fd4ab9bc2f69" xlink:href="amgn-20201231.xsd#amgn_DerivativeFinancialInstrumentsLiabilitiesFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_0430c5a9-f0d8-42bf-b2b9-693a2d793da2" xlink:to="loc_amgn_DerivativeFinancialInstrumentsLiabilitiesFairValueDisclosureAbstract_9341a38f-af1b-40f7-b09d-fd4ab9bc2f69" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCurrencyContractsLiabilityFairValueDisclosure_77d8ebbd-562c-42aa-907a-ee27235fff46" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ForeignCurrencyContractsLiabilityFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amgn_DerivativeFinancialInstrumentsLiabilitiesFairValueDisclosureAbstract_9341a38f-af1b-40f7-b09d-fd4ab9bc2f69" xlink:to="loc_us-gaap_ForeignCurrencyContractsLiabilityFairValueDisclosure_77d8ebbd-562c-42aa-907a-ee27235fff46" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateFairValueHedgeLiabilityAtFairValue_12b59f37-a7e4-49a4-82a8-b8187b35889b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestRateFairValueHedgeLiabilityAtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amgn_DerivativeFinancialInstrumentsLiabilitiesFairValueDisclosureAbstract_9341a38f-af1b-40f7-b09d-fd4ab9bc2f69" xlink:to="loc_us-gaap_InterestRateFairValueHedgeLiabilityAtFairValue_12b59f37-a7e4-49a4-82a8-b8187b35889b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_6dbc2935-1380-4d9a-aaa3-34f343997148" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_0430c5a9-f0d8-42bf-b2b9-693a2d793da2" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_6dbc2935-1380-4d9a-aaa3-34f343997148" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_811fa216-738d-410e-81b9-e88215f19cbc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_0430c5a9-f0d8-42bf-b2b9-693a2d793da2" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosure_811fa216-738d-410e-81b9-e88215f19cbc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_83dc08eb-f00e-4ec1-ab3b-281cfab810dd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_582e1e89-f983-409b-8ff0-a3e51a6cb5f7" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_83dc08eb-f00e-4ec1-ab3b-281cfab810dd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_10c46529-fd43-4a95-bfbf-56d67f32cac7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_83dc08eb-f00e-4ec1-ab3b-281cfab810dd" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_10c46529-fd43-4a95-bfbf-56d67f32cac7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_10c46529-fd43-4a95-bfbf-56d67f32cac7_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_10c46529-fd43-4a95-bfbf-56d67f32cac7" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_10c46529-fd43-4a95-bfbf-56d67f32cac7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_4ca24216-bfb5-4dae-9070-5053fc34d90d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_10c46529-fd43-4a95-bfbf-56d67f32cac7" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_4ca24216-bfb5-4dae-9070-5053fc34d90d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_f4978f21-9cb7-4ba1-b38b-328bf3f79d1d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_4ca24216-bfb5-4dae-9070-5053fc34d90d" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_f4978f21-9cb7-4ba1-b38b-328bf3f79d1d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_226f3c64-9abc-4aef-a225-0441c426292e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_4ca24216-bfb5-4dae-9070-5053fc34d90d" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_226f3c64-9abc-4aef-a225-0441c426292e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_2f212606-87cb-4cde-b20c-d1f88f7429f5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_4ca24216-bfb5-4dae-9070-5053fc34d90d" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_2f212606-87cb-4cde-b20c-d1f88f7429f5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_15f24ad3-1509-4e4b-8953-96e5ca7d9570" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_83dc08eb-f00e-4ec1-ab3b-281cfab810dd" xlink:to="loc_us-gaap_FinancialInstrumentAxis_15f24ad3-1509-4e4b-8953-96e5ca7d9570" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_15f24ad3-1509-4e4b-8953-96e5ca7d9570_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_15f24ad3-1509-4e4b-8953-96e5ca7d9570" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_15f24ad3-1509-4e4b-8953-96e5ca7d9570_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d6ddd4fa-1df5-4fcd-9ad9-b6d2b24d619c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_15f24ad3-1509-4e4b-8953-96e5ca7d9570" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d6ddd4fa-1df5-4fcd-9ad9-b6d2b24d619c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_b20bec62-e31c-46e1-ae0c-97bdcb17e69e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d6ddd4fa-1df5-4fcd-9ad9-b6d2b24d619c" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_b20bec62-e31c-46e1-ae0c-97bdcb17e69e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasuryBillSecuritiesMember_72dd3005-3d22-4a7e-9e74-f070ea435010" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_USTreasuryBillSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d6ddd4fa-1df5-4fcd-9ad9-b6d2b24d619c" xlink:to="loc_us-gaap_USTreasuryBillSecuritiesMember_72dd3005-3d22-4a7e-9e74-f070ea435010" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CorporateDebtSecuritiesFinancialMember_8cfabb71-9d43-4093-bc72-faa5a986f094" xlink:href="amgn-20201231.xsd#amgn_CorporateDebtSecuritiesFinancialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d6ddd4fa-1df5-4fcd-9ad9-b6d2b24d619c" xlink:to="loc_amgn_CorporateDebtSecuritiesFinancialMember_8cfabb71-9d43-4093-bc72-faa5a986f094" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CorporateDebtSecuritiesIndustrialMember_226339f4-1ed8-4e8c-b162-bcbd7cf15247" xlink:href="amgn-20201231.xsd#amgn_CorporateDebtSecuritiesIndustrialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d6ddd4fa-1df5-4fcd-9ad9-b6d2b24d619c" xlink:to="loc_amgn_CorporateDebtSecuritiesIndustrialMember_226339f4-1ed8-4e8c-b162-bcbd7cf15247" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CorporateDebtSecuritiesOtherMember_6002c581-457e-414d-804b-4e0bf2f8d0d5" xlink:href="amgn-20201231.xsd#amgn_CorporateDebtSecuritiesOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d6ddd4fa-1df5-4fcd-9ad9-b6d2b24d619c" xlink:to="loc_amgn_CorporateDebtSecuritiesOtherMember_6002c581-457e-414d-804b-4e0bf2f8d0d5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_d5c30c6e-34d5-441b-81fb-65bf02be799d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ResidentialMortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d6ddd4fa-1df5-4fcd-9ad9-b6d2b24d619c" xlink:to="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_d5c30c6e-34d5-441b-81fb-65bf02be799d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_229377de-443a-43b5-9c28-d517039bb9e9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d6ddd4fa-1df5-4fcd-9ad9-b6d2b24d619c" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_229377de-443a-43b5-9c28-d517039bb9e9" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsMember_126f5c56-2ad7-4f55-bd48-122d1174f54b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MoneyMarketFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d6ddd4fa-1df5-4fcd-9ad9-b6d2b24d619c" xlink:to="loc_us-gaap_MoneyMarketFundsMember_126f5c56-2ad7-4f55-bd48-122d1174f54b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_OtherShortTermInterestBearingSecuritiesMember_7cabaee8-97a1-41e7-a0ca-ff3202c8c9d4" xlink:href="amgn-20201231.xsd#amgn_OtherShortTermInterestBearingSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d6ddd4fa-1df5-4fcd-9ad9-b6d2b24d619c" xlink:to="loc_amgn_OtherShortTermInterestBearingSecuritiesMember_7cabaee8-97a1-41e7-a0ca-ff3202c8c9d4" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_78da90b6-8c9a-4aa5-8e65-1c342fbc25da" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_83dc08eb-f00e-4ec1-ab3b-281cfab810dd" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_78da90b6-8c9a-4aa5-8e65-1c342fbc25da" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_78da90b6-8c9a-4aa5-8e65-1c342fbc25da_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_78da90b6-8c9a-4aa5-8e65-1c342fbc25da" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_78da90b6-8c9a-4aa5-8e65-1c342fbc25da_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_aa13c50e-3fc0-4959-baba-bad40eebb907" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_78da90b6-8c9a-4aa5-8e65-1c342fbc25da" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_aa13c50e-3fc0-4959-baba-bad40eebb907" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeContractMember_10cacb78-ce32-4443-bf2e-1f2a50e3e48a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ForeignExchangeContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_aa13c50e-3fc0-4959-baba-bad40eebb907" xlink:to="loc_us-gaap_ForeignExchangeContractMember_10cacb78-ce32-4443-bf2e-1f2a50e3e48a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CrossCurrencySwapContractsMember_96f459ac-871b-4662-b7d1-cc49e1816616" xlink:href="amgn-20201231.xsd#amgn_CrossCurrencySwapContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_aa13c50e-3fc0-4959-baba-bad40eebb907" xlink:to="loc_amgn_CrossCurrencySwapContractsMember_96f459ac-871b-4662-b7d1-cc49e1816616" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_820a6906-effe-4f49-9dc1-e8821d35edff" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_aa13c50e-3fc0-4959-baba-bad40eebb907" xlink:to="loc_us-gaap_InterestRateSwapMember_820a6906-effe-4f49-9dc1-e8821d35edff" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/FairvaluemeasurementNarrativeDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#FairvaluemeasurementNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/FairvaluemeasurementNarrativeDetails" xlink:type="extended" id="i0e36488ed5c54ba6a67ac98b059cfb29_FairvaluemeasurementNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_58299a5f-0cb3-4714-abad-aa185b6f9794" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MaximumLengthOfTimeForeignCurrencyCashFlowHedge_bbcaa7d7-36a5-4123-a18a-9b62e8cdbef3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MaximumLengthOfTimeForeignCurrencyCashFlowHedge"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_58299a5f-0cb3-4714-abad-aa185b6f9794" xlink:to="loc_us-gaap_MaximumLengthOfTimeForeignCurrencyCashFlowHedge_bbcaa7d7-36a5-4123-a18a-9b62e8cdbef3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill_1588eb75-d60f-4b6f-9efe-869300d90147" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_58299a5f-0cb3-4714-abad-aa185b6f9794" xlink:to="loc_us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill_1588eb75-d60f-4b6f-9efe-869300d90147" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableFairValueDisclosure_1f89c9d2-8579-43c0-bbf7-7e5d1d1476cc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesPayableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_58299a5f-0cb3-4714-abad-aa185b6f9794" xlink:to="loc_us-gaap_NotesPayableFairValueDisclosure_1f89c9d2-8579-43c0-bbf7-7e5d1d1476cc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_d716c265-396f-4d39-94d9-ff5dfce19a3a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_58299a5f-0cb3-4714-abad-aa185b6f9794" xlink:to="loc_us-gaap_LongTermDebt_d716c265-396f-4d39-94d9-ff5dfce19a3a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentQuotedMarketValue_6df9f6dc-45ba-4b66-be0b-b04fab22b3ed" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvestmentQuotedMarketValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_58299a5f-0cb3-4714-abad-aa185b6f9794" xlink:to="loc_us-gaap_EquityMethodInvestmentQuotedMarketValue_6df9f6dc-45ba-4b66-be0b-b04fab22b3ed" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments_35713cd1-1601-4fba-91b9-75b62efc7e39" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_58299a5f-0cb3-4714-abad-aa185b6f9794" xlink:to="loc_us-gaap_EquityMethodInvestments_35713cd1-1601-4fba-91b9-75b62efc7e39" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_6a4950ae-d140-497e-ace7-7c750ad9974a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_58299a5f-0cb3-4714-abad-aa185b6f9794" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_6a4950ae-d140-497e-ace7-7c750ad9974a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_40b0b622-3c3b-426c-9f89-9b0b4fae48d9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_6a4950ae-d140-497e-ace7-7c750ad9974a" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_40b0b622-3c3b-426c-9f89-9b0b4fae48d9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_40b0b622-3c3b-426c-9f89-9b0b4fae48d9_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_40b0b622-3c3b-426c-9f89-9b0b4fae48d9" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_40b0b622-3c3b-426c-9f89-9b0b4fae48d9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_a3c85cba-cbcb-4f64-a926-eb96d4e2eebd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_40b0b622-3c3b-426c-9f89-9b0b4fae48d9" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_a3c85cba-cbcb-4f64-a926-eb96d4e2eebd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_BeiGeneMember_3f89c960-f275-4332-a898-e3d8992ba03f" xlink:href="amgn-20201231.xsd#amgn_BeiGeneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_a3c85cba-cbcb-4f64-a926-eb96d4e2eebd" xlink:to="loc_amgn_BeiGeneMember_3f89c960-f275-4332-a898-e3d8992ba03f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_e00696ae-e646-4d6e-8feb-750e25f04cb1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_6a4950ae-d140-497e-ace7-7c750ad9974a" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_e00696ae-e646-4d6e-8feb-750e25f04cb1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_e00696ae-e646-4d6e-8feb-750e25f04cb1_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_e00696ae-e646-4d6e-8feb-750e25f04cb1" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_e00696ae-e646-4d6e-8feb-750e25f04cb1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_4e4f141f-2c92-4208-91da-b744f6a6cf18" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_e00696ae-e646-4d6e-8feb-750e25f04cb1" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_4e4f141f-2c92-4208-91da-b744f6a6cf18" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherOperatingIncomeExpenseMember_7c38b022-bd36-4d4b-92d2-565e2f1561f2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherOperatingIncomeExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_4e4f141f-2c92-4208-91da-b744f6a6cf18" xlink:to="loc_us-gaap_OtherOperatingIncomeExpenseMember_7c38b022-bd36-4d4b-92d2-565e2f1561f2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_0c0c9568-21d8-4149-b549-9fd73afdb9cf" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_6a4950ae-d140-497e-ace7-7c750ad9974a" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_0c0c9568-21d8-4149-b549-9fd73afdb9cf" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_0c0c9568-21d8-4149-b549-9fd73afdb9cf_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_0c0c9568-21d8-4149-b549-9fd73afdb9cf" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_0c0c9568-21d8-4149-b549-9fd73afdb9cf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_b3ee3d15-9f8a-4895-8418-3c52b0b70d6e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_0c0c9568-21d8-4149-b549-9fd73afdb9cf" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_b3ee3d15-9f8a-4895-8418-3c52b0b70d6e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InProcessResearchAndDevelopmentMember_a6b40991-7ae8-4c28-bbce-414b7f43cdfb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InProcessResearchAndDevelopmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_b3ee3d15-9f8a-4895-8418-3c52b0b70d6e" xlink:to="loc_us-gaap_InProcessResearchAndDevelopmentMember_a6b40991-7ae8-4c28-bbce-414b7f43cdfb" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/Derivativeinstruments" xlink:type="simple" xlink:href="amgn-20201231.xsd#Derivativeinstruments"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/Derivativeinstruments" xlink:type="extended" id="i42a3bd612cae4eed82855d574121e751_Derivativeinstruments"/>
  <link:roleRef roleURI="http://www.amgen.com/role/DerivativeinstrumentsTables" xlink:type="simple" xlink:href="amgn-20201231.xsd#DerivativeinstrumentsTables"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/DerivativeinstrumentsTables" xlink:type="extended" id="i245545e32f924aea97d645c97c7cd91a_DerivativeinstrumentsTables"/>
  <link:roleRef roleURI="http://www.amgen.com/role/DerivativeinstrumentsNarrativeDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#DerivativeinstrumentsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/DerivativeinstrumentsNarrativeDetails" xlink:type="extended" id="i20dee2bcc38043c8873295b4a355cf69_DerivativeinstrumentsNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_a300fff2-e9ce-44a4-a359-714950bfc6f7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_efabe922-4d5e-440c-bb85-53b63bf9b37b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_a300fff2-e9ce-44a4-a359-714950bfc6f7" xlink:to="loc_us-gaap_DerivativeNotionalAmount_efabe922-4d5e-440c-bb85-53b63bf9b37b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_a1807b58-2c79-4fdc-beb1-f7bf63721056" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_a300fff2-e9ce-44a4-a359-714950bfc6f7" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_a1807b58-2c79-4fdc-beb1-f7bf63721056" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_DerivativeNotionalAmountAmountTerminated_f71440e6-6dee-41b1-9c59-9821a05606f3" xlink:href="amgn-20201231.xsd#amgn_DerivativeNotionalAmountAmountTerminated"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_a300fff2-e9ce-44a4-a359-714950bfc6f7" xlink:to="loc_amgn_DerivativeNotionalAmountAmountTerminated_f71440e6-6dee-41b1-9c59-9821a05606f3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_6976cf1a-9eb4-4a5b-9ede-b640a8ff55b3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_a300fff2-e9ce-44a4-a359-714950bfc6f7" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_6976cf1a-9eb4-4a5b-9ede-b640a8ff55b3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeGainOnDerivative_eefb5416-9f1f-4b7a-8bd5-d401ad8bbac3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeGainOnDerivative"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_a300fff2-e9ce-44a4-a359-714950bfc6f7" xlink:to="loc_us-gaap_DerivativeGainOnDerivative_eefb5416-9f1f-4b7a-8bd5-d401ad8bbac3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_DerivativeNotionalAmountAmountTerminatedResultingInNetCashProvidedByOperatingActivities_28e44bc0-169f-431a-9663-10d5a3ac9e16" xlink:href="amgn-20201231.xsd#amgn_DerivativeNotionalAmountAmountTerminatedResultingInNetCashProvidedByOperatingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_a300fff2-e9ce-44a4-a359-714950bfc6f7" xlink:to="loc_amgn_DerivativeNotionalAmountAmountTerminatedResultingInNetCashProvidedByOperatingActivities_28e44bc0-169f-431a-9663-10d5a3ac9e16" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgedLiabilityFairValueHedge_14ffd8f1-6efc-4a5d-a3e1-34b7cdd6d199" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgedLiabilityFairValueHedge"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_a300fff2-e9ce-44a4-a359-714950bfc6f7" xlink:to="loc_us-gaap_HedgedLiabilityFairValueHedge_14ffd8f1-6efc-4a5d-a3e1-34b7cdd6d199" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCurrencyCashFlowHedgeGainLossToBeReclassifiedDuringNext12Months_e3be4ea4-5435-4706-aaec-399c9364a0a0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ForeignCurrencyCashFlowHedgeGainLossToBeReclassifiedDuringNext12Months"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_a300fff2-e9ce-44a4-a359-714950bfc6f7" xlink:to="loc_us-gaap_ForeignCurrencyCashFlowHedgeGainLossToBeReclassifiedDuringNext12Months_e3be4ea4-5435-4706-aaec-399c9364a0a0" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_0d68378b-57ed-43db-ac9d-969869c3ec7e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_a300fff2-e9ce-44a4-a359-714950bfc6f7" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_0d68378b-57ed-43db-ac9d-969869c3ec7e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_431824cc-2147-4d29-aa7c-80565620037b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_0d68378b-57ed-43db-ac9d-969869c3ec7e" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_431824cc-2147-4d29-aa7c-80565620037b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_431824cc-2147-4d29-aa7c-80565620037b_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_431824cc-2147-4d29-aa7c-80565620037b" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_431824cc-2147-4d29-aa7c-80565620037b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_1a8ba0d8-1b82-45d5-847c-58f899dfcb9b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_431824cc-2147-4d29-aa7c-80565620037b" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_1a8ba0d8-1b82-45d5-847c-58f899dfcb9b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableToBanksMember_1ba64535-da34-4055-b2a6-cc2f11371ea9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesPayableToBanksMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_1a8ba0d8-1b82-45d5-847c-58f899dfcb9b" xlink:to="loc_us-gaap_NotesPayableToBanksMember_1ba64535-da34-4055-b2a6-cc2f11371ea9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_efcb2f6a-7102-4dd2-80de-b8c45b3aa6b7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_0d68378b-57ed-43db-ac9d-969869c3ec7e" xlink:to="loc_us-gaap_DebtInstrumentAxis_efcb2f6a-7102-4dd2-80de-b8c45b3aa6b7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_efcb2f6a-7102-4dd2-80de-b8c45b3aa6b7_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_efcb2f6a-7102-4dd2-80de-b8c45b3aa6b7" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_efcb2f6a-7102-4dd2-80de-b8c45b3aa6b7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_c7d2a1e1-d019-4d43-9c89-a782dcbab918" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_efcb2f6a-7102-4dd2-80de-b8c45b3aa6b7" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_c7d2a1e1-d019-4d43-9c89-a782dcbab918" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointOneTwoFivePercentEuroNotesDue2019Member_da66e5e9-4520-4725-a327-63bf46453ecb" xlink:href="amgn-20201231.xsd#amgn_TwoPointOneTwoFivePercentEuroNotesDue2019Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_c7d2a1e1-d019-4d43-9c89-a782dcbab918" xlink:to="loc_amgn_TwoPointOneTwoFivePercentEuroNotesDue2019Member_da66e5e9-4520-4725-a327-63bf46453ecb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_e2bb15bf-05f3-4086-a2ed-d8ac31dd6c5c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_0d68378b-57ed-43db-ac9d-969869c3ec7e" xlink:to="loc_us-gaap_HedgingDesignationAxis_e2bb15bf-05f3-4086-a2ed-d8ac31dd6c5c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_e2bb15bf-05f3-4086-a2ed-d8ac31dd6c5c_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_e2bb15bf-05f3-4086-a2ed-d8ac31dd6c5c" xlink:to="loc_us-gaap_HedgingDesignationDomain_e2bb15bf-05f3-4086-a2ed-d8ac31dd6c5c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_a9317e5d-d70f-420d-8d98-f2eb6bdd86bc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_e2bb15bf-05f3-4086-a2ed-d8ac31dd6c5c" xlink:to="loc_us-gaap_HedgingDesignationDomain_a9317e5d-d70f-420d-8d98-f2eb6bdd86bc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_40de7323-726b-41b5-be13-302ec7121ce4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_a9317e5d-d70f-420d-8d98-f2eb6bdd86bc" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_40de7323-726b-41b5-be13-302ec7121ce4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_f226973a-86b6-4f9c-81e4-b22c900f9864" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_a9317e5d-d70f-420d-8d98-f2eb6bdd86bc" xlink:to="loc_us-gaap_NondesignatedMember_f226973a-86b6-4f9c-81e4-b22c900f9864" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_1bf44161-8dd5-4d4e-85aa-846a96c62b5f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_0d68378b-57ed-43db-ac9d-969869c3ec7e" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_1bf44161-8dd5-4d4e-85aa-846a96c62b5f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_1bf44161-8dd5-4d4e-85aa-846a96c62b5f_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_1bf44161-8dd5-4d4e-85aa-846a96c62b5f" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_1bf44161-8dd5-4d4e-85aa-846a96c62b5f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_c8ca402b-37f1-4555-abf5-bb20998d1d35" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_1bf44161-8dd5-4d4e-85aa-846a96c62b5f" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_c8ca402b-37f1-4555-abf5-bb20998d1d35" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForwardContractsMember_db0f7810-7ca0-427f-9a2e-4fec645f9d72" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ForwardContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_c8ca402b-37f1-4555-abf5-bb20998d1d35" xlink:to="loc_us-gaap_ForwardContractsMember_db0f7810-7ca0-427f-9a2e-4fec645f9d72" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OptionMember_3cbf0f85-2195-4856-b537-5fe1eab07fc3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_c8ca402b-37f1-4555-abf5-bb20998d1d35" xlink:to="loc_us-gaap_OptionMember_3cbf0f85-2195-4856-b537-5fe1eab07fc3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ForeignCurrencyAndCrossCurrencySwapsMember_a6306c02-468b-42e3-b336-610c35bb3cec" xlink:href="amgn-20201231.xsd#amgn_ForeignCurrencyAndCrossCurrencySwapsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_c8ca402b-37f1-4555-abf5-bb20998d1d35" xlink:to="loc_amgn_ForeignCurrencyAndCrossCurrencySwapsMember_a6306c02-468b-42e3-b336-610c35bb3cec" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_3ece5595-5d4c-4d06-973a-ed0388b34369" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_c8ca402b-37f1-4555-abf5-bb20998d1d35" xlink:to="loc_us-gaap_InterestRateSwapMember_3ece5595-5d4c-4d06-973a-ed0388b34369" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_InterestRateSwapAtThenCurrentInterestRatesMember_c6c82309-d1a1-4da1-8250-7c78d9816926" xlink:href="amgn-20201231.xsd#amgn_InterestRateSwapAtThenCurrentInterestRatesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_c8ca402b-37f1-4555-abf5-bb20998d1d35" xlink:to="loc_amgn_InterestRateSwapAtThenCurrentInterestRatesMember_c6c82309-d1a1-4da1-8250-7c78d9816926" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_InterestRateSwapAxis_52d02d05-bed7-4edd-a683-e2062e25e51f" xlink:href="amgn-20201231.xsd#amgn_InterestRateSwapAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_0d68378b-57ed-43db-ac9d-969869c3ec7e" xlink:to="loc_amgn_InterestRateSwapAxis_52d02d05-bed7-4edd-a683-e2062e25e51f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_InterestRateSwapDomain_52d02d05-bed7-4edd-a683-e2062e25e51f_default" xlink:href="amgn-20201231.xsd#amgn_InterestRateSwapDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_amgn_InterestRateSwapAxis_52d02d05-bed7-4edd-a683-e2062e25e51f" xlink:to="loc_amgn_InterestRateSwapDomain_52d02d05-bed7-4edd-a683-e2062e25e51f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_InterestRateSwapDomain_681d2a65-dc60-4c8a-b038-3a4687d47d21" xlink:href="amgn-20201231.xsd#amgn_InterestRateSwapDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_amgn_InterestRateSwapAxis_52d02d05-bed7-4edd-a683-e2062e25e51f" xlink:to="loc_amgn_InterestRateSwapDomain_681d2a65-dc60-4c8a-b038-3a4687d47d21" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_InterestRateSwapTwoMember_70452a64-9655-4046-8767-6d57de7001a6" xlink:href="amgn-20201231.xsd#amgn_InterestRateSwapTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amgn_InterestRateSwapDomain_681d2a65-dc60-4c8a-b038-3a4687d47d21" xlink:to="loc_amgn_InterestRateSwapTwoMember_70452a64-9655-4046-8767-6d57de7001a6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_056039a5-3d8b-4ded-9b78-4e467a978bd2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_0d68378b-57ed-43db-ac9d-969869c3ec7e" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_056039a5-3d8b-4ded-9b78-4e467a978bd2" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_056039a5-3d8b-4ded-9b78-4e467a978bd2_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_056039a5-3d8b-4ded-9b78-4e467a978bd2" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_056039a5-3d8b-4ded-9b78-4e467a978bd2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_a60bd776-f05c-4663-81df-e8a00a7d7e7d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_056039a5-3d8b-4ded-9b78-4e467a978bd2" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_a60bd776-f05c-4663-81df-e8a00a7d7e7d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseMember_60f8d77e-4505-42a0-8dc8-eb5029fa8769" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_a60bd776-f05c-4663-81df-e8a00a7d7e7d" xlink:to="loc_us-gaap_InterestExpenseMember_60f8d77e-4505-42a0-8dc8-eb5029fa8769" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByLiabilityClassAxis_25b8af99-f939-47b4-9032-40ca36106160" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByLiabilityClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_0d68378b-57ed-43db-ac9d-969869c3ec7e" xlink:to="loc_us-gaap_FairValueByLiabilityClassAxis_25b8af99-f939-47b4-9032-40ca36106160" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_25b8af99-f939-47b4-9032-40ca36106160_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_25b8af99-f939-47b4-9032-40ca36106160" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_25b8af99-f939-47b4-9032-40ca36106160_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_7ccb6400-d8fa-4b4f-837f-c60fc40e0197" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_25b8af99-f939-47b4-9032-40ca36106160" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_7ccb6400-d8fa-4b4f-837f-c60fc40e0197" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMember_3704f89c-697a-4c28-be9b-a063ca37beae" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_7ccb6400-d8fa-4b4f-837f-c60fc40e0197" xlink:to="loc_us-gaap_LongTermDebtMember_3704f89c-697a-4c28-be9b-a063ca37beae" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/DerivativeinstrumentsCrosscurrencySwapsDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#DerivativeinstrumentsCrosscurrencySwapsDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/DerivativeinstrumentsCrosscurrencySwapsDetails" xlink:type="extended" id="i398a6cbf2dba4533bfb741258ce1b8b0_DerivativeinstrumentsCrosscurrencySwapsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_bcc50943-d2b5-44ab-9836-e638db07eb78" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_20fae692-800c-4d91-bdb3-d7f7a6ce4a1a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_bcc50943-d2b5-44ab-9836-e638db07eb78" xlink:to="loc_us-gaap_DerivativeNotionalAmount_20fae692-800c-4d91-bdb3-d7f7a6ce4a1a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFixedInterestRate_2a585601-2261-4a92-b1cb-7e616beb116c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeFixedInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_bcc50943-d2b5-44ab-9836-e638db07eb78" xlink:to="loc_us-gaap_DerivativeFixedInterestRate_2a585601-2261-4a92-b1cb-7e616beb116c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_174a4d4d-68d4-4078-acf4-07f543d6caeb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_bcc50943-d2b5-44ab-9836-e638db07eb78" xlink:to="loc_us-gaap_DerivativeTable_174a4d4d-68d4-4078-acf4-07f543d6caeb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_bc7659ed-ec0b-47c5-a472-b2e34db21106" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_174a4d4d-68d4-4078-acf4-07f543d6caeb" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_bc7659ed-ec0b-47c5-a472-b2e34db21106" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_bc7659ed-ec0b-47c5-a472-b2e34db21106_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_bc7659ed-ec0b-47c5-a472-b2e34db21106" xlink:to="loc_us-gaap_HedgingRelationshipDomain_bc7659ed-ec0b-47c5-a472-b2e34db21106_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_9256fa86-c9ce-47f5-89c3-54984bdacbd0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_bc7659ed-ec0b-47c5-a472-b2e34db21106" xlink:to="loc_us-gaap_HedgingRelationshipDomain_9256fa86-c9ce-47f5-89c3-54984bdacbd0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgingMember_5d4ae16e-6e0e-4d8d-8ca7-acfd1f8d28b5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashFlowHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_9256fa86-c9ce-47f5-89c3-54984bdacbd0" xlink:to="loc_us-gaap_CashFlowHedgingMember_5d4ae16e-6e0e-4d8d-8ca7-acfd1f8d28b5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_ba7cbd77-9b2a-4145-bef0-dedf48b6b4c0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_174a4d4d-68d4-4078-acf4-07f543d6caeb" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_ba7cbd77-9b2a-4145-bef0-dedf48b6b4c0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_ba7cbd77-9b2a-4145-bef0-dedf48b6b4c0_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_ba7cbd77-9b2a-4145-bef0-dedf48b6b4c0" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_ba7cbd77-9b2a-4145-bef0-dedf48b6b4c0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_41819d06-b06b-4f32-95d3-874640a01988" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_ba7cbd77-9b2a-4145-bef0-dedf48b6b4c0" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_41819d06-b06b-4f32-95d3-874640a01988" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CrossCurrencySwapContractsMember_db85d4c7-5ea7-4772-be0f-1d0bde5b06fd" xlink:href="amgn-20201231.xsd#amgn_CrossCurrencySwapContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_41819d06-b06b-4f32-95d3-874640a01988" xlink:to="loc_amgn_CrossCurrencySwapContractsMember_db85d4c7-5ea7-4772-be0f-1d0bde5b06fd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CurrencyAxis_108e6710-753b-4bdc-93f6-65a0d6857ad0" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CurrencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_174a4d4d-68d4-4078-acf4-07f543d6caeb" xlink:to="loc_srt_CurrencyAxis_108e6710-753b-4bdc-93f6-65a0d6857ad0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_currency_AllCurrenciesDomain_108e6710-753b-4bdc-93f6-65a0d6857ad0_default" xlink:href="https://xbrl.sec.gov/currency/2020/currency-2020-01-31.xsd#currency_AllCurrenciesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CurrencyAxis_108e6710-753b-4bdc-93f6-65a0d6857ad0" xlink:to="loc_currency_AllCurrenciesDomain_108e6710-753b-4bdc-93f6-65a0d6857ad0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_currency_AllCurrenciesDomain_94ab1f4a-20d7-49ea-80a4-53c7b4652352" xlink:href="https://xbrl.sec.gov/currency/2020/currency-2020-01-31.xsd#currency_AllCurrenciesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CurrencyAxis_108e6710-753b-4bdc-93f6-65a0d6857ad0" xlink:to="loc_currency_AllCurrenciesDomain_94ab1f4a-20d7-49ea-80a4-53c7b4652352" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_currency_EUR_26e0fc49-2000-4df5-9078-5afdf3c6d97b" xlink:href="https://xbrl.sec.gov/currency/2020/currency-2020-01-31.xsd#currency_EUR"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_currency_AllCurrenciesDomain_94ab1f4a-20d7-49ea-80a4-53c7b4652352" xlink:to="loc_currency_EUR_26e0fc49-2000-4df5-9078-5afdf3c6d97b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_currency_CHF_8ceb6f5f-36dc-4fcb-bd9f-42e296860c2f" xlink:href="https://xbrl.sec.gov/currency/2020/currency-2020-01-31.xsd#currency_CHF"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_currency_AllCurrenciesDomain_94ab1f4a-20d7-49ea-80a4-53c7b4652352" xlink:to="loc_currency_CHF_8ceb6f5f-36dc-4fcb-bd9f-42e296860c2f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_currency_GBP_4046fc36-ac96-4d0b-a917-161c94b5688f" xlink:href="https://xbrl.sec.gov/currency/2020/currency-2020-01-31.xsd#currency_GBP"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_currency_AllCurrenciesDomain_94ab1f4a-20d7-49ea-80a4-53c7b4652352" xlink:to="loc_currency_GBP_4046fc36-ac96-4d0b-a917-161c94b5688f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_currency_USD_d42e15fa-9e5b-46fb-8d09-c821bb540842" xlink:href="https://xbrl.sec.gov/currency/2020/currency-2020-01-31.xsd#currency_USD"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_currency_AllCurrenciesDomain_94ab1f4a-20d7-49ea-80a4-53c7b4652352" xlink:to="loc_currency_USD_d42e15fa-9e5b-46fb-8d09-c821bb540842" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_ddac7831-341c-4876-864a-ab987f6aca94" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_174a4d4d-68d4-4078-acf4-07f543d6caeb" xlink:to="loc_us-gaap_DebtInstrumentAxis_ddac7831-341c-4876-864a-ab987f6aca94" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_ddac7831-341c-4876-864a-ab987f6aca94_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_ddac7831-341c-4876-864a-ab987f6aca94" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_ddac7831-341c-4876-864a-ab987f6aca94_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_0c99b8e4-8bf3-4c27-af7b-c730e48151d5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_ddac7831-341c-4876-864a-ab987f6aca94" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_0c99b8e4-8bf3-4c27-af7b-c730e48151d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPointOneTwoFivePercentEuroNotesDue2019Member_8d3d189f-37e2-4534-b7c3-eb70b8fdf411" xlink:href="amgn-20201231.xsd#amgn_TwoPointOneTwoFivePercentEuroNotesDue2019Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_0c99b8e4-8bf3-4c27-af7b-c730e48151d5" xlink:to="loc_amgn_TwoPointOneTwoFivePercentEuroNotesDue2019Member_8d3d189f-37e2-4534-b7c3-eb70b8fdf411" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_OnePointTwentyFivePercentEuroNotesDueTwoThousandTwentyTwoMember_ac779fbd-5964-41c2-821d-dd7d1eafa99f" xlink:href="amgn-20201231.xsd#amgn_OnePointTwentyFivePercentEuroNotesDueTwoThousandTwentyTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_0c99b8e4-8bf3-4c27-af7b-c730e48151d5" xlink:to="loc_amgn_OnePointTwentyFivePercentEuroNotesDueTwoThousandTwentyTwoMember_ac779fbd-5964-41c2-821d-dd7d1eafa99f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ZeroPointFortyOnePercentSwissFrancBondsDueTwoThousandTwentyThreeMember_6ebe90b3-1a98-4b7e-ab52-98041f08045e" xlink:href="amgn-20201231.xsd#amgn_ZeroPointFortyOnePercentSwissFrancBondsDueTwoThousandTwentyThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_0c99b8e4-8bf3-4c27-af7b-c730e48151d5" xlink:to="loc_amgn_ZeroPointFortyOnePercentSwissFrancBondsDueTwoThousandTwentyThreeMember_6ebe90b3-1a98-4b7e-ab52-98041f08045e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_TwoPercentEuroNotesDueTwoThousandTwentySixMember_83183661-00ef-456f-a78b-7dae300c5f27" xlink:href="amgn-20201231.xsd#amgn_TwoPercentEuroNotesDueTwoThousandTwentySixMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_0c99b8e4-8bf3-4c27-af7b-c730e48151d5" xlink:to="loc_amgn_TwoPercentEuroNotesDueTwoThousandTwentySixMember_83183661-00ef-456f-a78b-7dae300c5f27" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FivePointFiveZeroPercentPoundSterlingNotesDue2026Member_db73a217-eab3-4fd5-80f5-81183a9b91c1" xlink:href="amgn-20201231.xsd#amgn_FivePointFiveZeroPercentPoundSterlingNotesDue2026Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_0c99b8e4-8bf3-4c27-af7b-c730e48151d5" xlink:to="loc_amgn_FivePointFiveZeroPercentPoundSterlingNotesDue2026Member_db73a217-eab3-4fd5-80f5-81183a9b91c1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FourPercentPoundSterlingNotesDue2029Member_6f0715cd-5f43-438b-b452-8730a4e6d6f0" xlink:href="amgn-20201231.xsd#amgn_FourPercentPoundSterlingNotesDue2029Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_0c99b8e4-8bf3-4c27-af7b-c730e48151d5" xlink:to="loc_amgn_FourPercentPoundSterlingNotesDue2029Member_6f0715cd-5f43-438b-b452-8730a4e6d6f0" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/DerivativeinstrumentsEffectivePortionofUnrealizedGainLossDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#DerivativeinstrumentsEffectivePortionofUnrealizedGainLossDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/DerivativeinstrumentsEffectivePortionofUnrealizedGainLossDetails" xlink:type="extended" id="i6ee19948b8c24261b38cabd8cc3cd155_DerivativeinstrumentsEffectivePortionofUnrealizedGainLossDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_9768fd1d-3b69-43bc-8635-85ea68a6f4a2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax_9a7235c8-1211-4f32-8dc6-937d3ede91eb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_9768fd1d-3b69-43bc-8635-85ea68a6f4a2" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax_9a7235c8-1211-4f32-8dc6-937d3ede91eb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_7f285b37-1237-4657-93d6-4fe34ce01bda" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_9768fd1d-3b69-43bc-8635-85ea68a6f4a2" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_7f285b37-1237-4657-93d6-4fe34ce01bda" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_353f4f60-a2b3-456b-9c17-9ad8a848ff92" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_7f285b37-1237-4657-93d6-4fe34ce01bda" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_353f4f60-a2b3-456b-9c17-9ad8a848ff92" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_353f4f60-a2b3-456b-9c17-9ad8a848ff92_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_353f4f60-a2b3-456b-9c17-9ad8a848ff92" xlink:to="loc_us-gaap_HedgingRelationshipDomain_353f4f60-a2b3-456b-9c17-9ad8a848ff92_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_dfded723-7323-48b2-91de-7f4a62bc7369" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_353f4f60-a2b3-456b-9c17-9ad8a848ff92" xlink:to="loc_us-gaap_HedgingRelationshipDomain_dfded723-7323-48b2-91de-7f4a62bc7369" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgingMember_1cf12b15-3c68-417e-8174-edf488aa93cf" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashFlowHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_dfded723-7323-48b2-91de-7f4a62bc7369" xlink:to="loc_us-gaap_CashFlowHedgingMember_1cf12b15-3c68-417e-8174-edf488aa93cf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_67c2b7de-e3d4-491c-be05-dc0924f226b5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_7f285b37-1237-4657-93d6-4fe34ce01bda" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_67c2b7de-e3d4-491c-be05-dc0924f226b5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_67c2b7de-e3d4-491c-be05-dc0924f226b5_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_67c2b7de-e3d4-491c-be05-dc0924f226b5" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_67c2b7de-e3d4-491c-be05-dc0924f226b5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_cbc32c71-9405-46e0-8d7e-796c45fb402c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_67c2b7de-e3d4-491c-be05-dc0924f226b5" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_cbc32c71-9405-46e0-8d7e-796c45fb402c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeContractMember_d6ece120-e5ff-48be-a562-237f72fc4ce4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ForeignExchangeContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_cbc32c71-9405-46e0-8d7e-796c45fb402c" xlink:to="loc_us-gaap_ForeignExchangeContractMember_d6ece120-e5ff-48be-a562-237f72fc4ce4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CrossCurrencySwapContractsMember_a957a2bf-f1de-4d25-bbba-448a1dda3cca" xlink:href="amgn-20201231.xsd#amgn_CrossCurrencySwapContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_cbc32c71-9405-46e0-8d7e-796c45fb402c" xlink:to="loc_amgn_CrossCurrencySwapContractsMember_a957a2bf-f1de-4d25-bbba-448a1dda3cca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ForwardInterestRateContractMember_50ce46dc-ff76-4852-bbbc-c067e213f9c2" xlink:href="amgn-20201231.xsd#amgn_ForwardInterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_cbc32c71-9405-46e0-8d7e-796c45fb402c" xlink:to="loc_amgn_ForwardInterestRateContractMember_50ce46dc-ff76-4852-bbbc-c067e213f9c2" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/DerivativeinstrumentsHedgedLiabilitiesandCumulativeAmountDetailsDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#DerivativeinstrumentsHedgedLiabilitiesandCumulativeAmountDetailsDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/DerivativeinstrumentsHedgedLiabilitiesandCumulativeAmountDetailsDetails" xlink:type="extended" id="i8dc9291041d24ded816500077f57ce5b_DerivativeinstrumentsHedgedLiabilitiesandCumulativeAmountDetailsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_b59f86aa-45d1-48a6-be86-96748f635b48" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgedLiabilityFairValueHedge_dfedaef4-b3fe-4b66-b9b5-9b4a9c586f3d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgedLiabilityFairValueHedge"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_b59f86aa-45d1-48a6-be86-96748f635b48" xlink:to="loc_us-gaap_HedgedLiabilityFairValueHedge_dfedaef4-b3fe-4b66-b9b5-9b4a9c586f3d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease_33ebaa0f-eb8b-449b-af27-89fdaa8d78ae" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_b59f86aa-45d1-48a6-be86-96748f635b48" xlink:to="loc_us-gaap_HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease_33ebaa0f-eb8b-449b-af27-89fdaa8d78ae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_HedgedLiabilityDiscontinuedFairValueHedge_e1af43cf-bf48-4f98-82b7-8711fb710b40" xlink:href="amgn-20201231.xsd#amgn_HedgedLiabilityDiscontinuedFairValueHedge"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_b59f86aa-45d1-48a6-be86-96748f635b48" xlink:to="loc_amgn_HedgedLiabilityDiscontinuedFairValueHedge_e1af43cf-bf48-4f98-82b7-8711fb710b40" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgedLiabilityDiscontinuedFairValueHedgeCumulativeIncreaseDecrease_8ecd1a9e-f1fe-45c6-910a-d143727b2e7b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgedLiabilityDiscontinuedFairValueHedgeCumulativeIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_b59f86aa-45d1-48a6-be86-96748f635b48" xlink:to="loc_us-gaap_HedgedLiabilityDiscontinuedFairValueHedgeCumulativeIncreaseDecrease_8ecd1a9e-f1fe-45c6-910a-d143727b2e7b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_244c70fc-2224-4d25-b0c3-685f1e605471" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_b59f86aa-45d1-48a6-be86-96748f635b48" xlink:to="loc_us-gaap_DerivativeTable_244c70fc-2224-4d25-b0c3-685f1e605471" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByLiabilityClassAxis_b339ca4d-994d-4327-910c-23c3badd98be" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByLiabilityClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_244c70fc-2224-4d25-b0c3-685f1e605471" xlink:to="loc_us-gaap_FairValueByLiabilityClassAxis_b339ca4d-994d-4327-910c-23c3badd98be" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_b339ca4d-994d-4327-910c-23c3badd98be_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_b339ca4d-994d-4327-910c-23c3badd98be" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_b339ca4d-994d-4327-910c-23c3badd98be_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_d561e0e4-d6df-4f84-ae0b-72266ee995d8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_b339ca4d-994d-4327-910c-23c3badd98be" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_d561e0e4-d6df-4f84-ae0b-72266ee995d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_LongTermDebtCurrentMaturitiesMember_e0b44485-78f4-44fb-a75b-302d5bc1abf5" xlink:href="amgn-20201231.xsd#amgn_LongTermDebtCurrentMaturitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_d561e0e4-d6df-4f84-ae0b-72266ee995d8" xlink:to="loc_amgn_LongTermDebtCurrentMaturitiesMember_e0b44485-78f4-44fb-a75b-302d5bc1abf5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMember_2a61c8c2-8c7b-4d0e-bf9b-058e165d610a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_d561e0e4-d6df-4f84-ae0b-72266ee995d8" xlink:to="loc_us-gaap_LongTermDebtMember_2a61c8c2-8c7b-4d0e-bf9b-058e165d610a" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/DerivativeinstrumentsSummaryofIncomeandExpenseLineItemsDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#DerivativeinstrumentsSummaryofIncomeandExpenseLineItemsDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/DerivativeinstrumentsSummaryofIncomeandExpenseLineItemsDetails" xlink:type="extended" id="i79ae9348298b465faf272113c040325f_DerivativeinstrumentsSummaryofIncomeandExpenseLineItemsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_bfd333f2-ea0e-47e6-b84d-cb9ca68b914c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_0f8c5396-6bda-4814-bd8e-523bd37fb479" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_bfd333f2-ea0e-47e6-b84d-cb9ca68b914c" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_0f8c5396-6bda-4814-bd8e-523bd37fb479" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_85001156-b3d8-4e9d-8704-061ab9498e91" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_bfd333f2-ea0e-47e6-b84d-cb9ca68b914c" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_85001156-b3d8-4e9d-8704-061ab9498e91" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebt_dffdd79c-db7a-4523-8194-995a78f436b9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_bfd333f2-ea0e-47e6-b84d-cb9ca68b914c" xlink:to="loc_us-gaap_InterestExpenseDebt_dffdd79c-db7a-4523-8194-995a78f436b9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ChangeInUnrealizedGainLossOnHedgedItemInFairValueHedge1_bcf12f61-53ff-4363-a471-a612d219f94e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ChangeInUnrealizedGainLossOnHedgedItemInFairValueHedge1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_bfd333f2-ea0e-47e6-b84d-cb9ca68b914c" xlink:to="loc_us-gaap_ChangeInUnrealizedGainLossOnHedgedItemInFairValueHedge1_bcf12f61-53ff-4363-a471-a612d219f94e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ChangeInUnrealizedGainLossOnFairValueHedgingInstruments1_0d7fabe0-b926-4a78-a250-94e8dd32c688" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ChangeInUnrealizedGainLossOnFairValueHedgingInstruments1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_bfd333f2-ea0e-47e6-b84d-cb9ca68b914c" xlink:to="loc_us-gaap_ChangeInUnrealizedGainLossOnFairValueHedgingInstruments1_0d7fabe0-b926-4a78-a250-94e8dd32c688" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_8846975f-5274-4714-898f-ffcb20e767a7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_bfd333f2-ea0e-47e6-b84d-cb9ca68b914c" xlink:to="loc_us-gaap_DerivativeTable_8846975f-5274-4714-898f-ffcb20e767a7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_05d464ce-84f2-4178-8511-8d853b48bc16" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_8846975f-5274-4714-898f-ffcb20e767a7" xlink:to="loc_srt_ProductOrServiceAxis_05d464ce-84f2-4178-8511-8d853b48bc16" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_05d464ce-84f2-4178-8511-8d853b48bc16_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_05d464ce-84f2-4178-8511-8d853b48bc16" xlink:to="loc_srt_ProductsAndServicesDomain_05d464ce-84f2-4178-8511-8d853b48bc16_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_291ab721-825c-442a-98ab-3cbd4a31f240" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_05d464ce-84f2-4178-8511-8d853b48bc16" xlink:to="loc_srt_ProductsAndServicesDomain_291ab721-825c-442a-98ab-3cbd4a31f240" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductMember_85753043-ff38-4f01-bb1d-92ec0e4f689f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_291ab721-825c-442a-98ab-3cbd4a31f240" xlink:to="loc_us-gaap_ProductMember_85753043-ff38-4f01-bb1d-92ec0e4f689f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_eb240656-a084-47cd-a858-45afe58faacb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_8846975f-5274-4714-898f-ffcb20e767a7" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_eb240656-a084-47cd-a858-45afe58faacb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_eb240656-a084-47cd-a858-45afe58faacb_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_eb240656-a084-47cd-a858-45afe58faacb" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_eb240656-a084-47cd-a858-45afe58faacb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_d09e0772-85f8-403a-b55c-7ef8c26fc104" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_eb240656-a084-47cd-a858-45afe58faacb" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_d09e0772-85f8-403a-b55c-7ef8c26fc104" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_28b045c3-e54d-4ca8-98c5-d7442efdf3ea" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_d09e0772-85f8-403a-b55c-7ef8c26fc104" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_28b045c3-e54d-4ca8-98c5-d7442efdf3ea" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_c2877098-d8c4-49f3-9900-fe3e1e4a12de" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_8846975f-5274-4714-898f-ffcb20e767a7" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_c2877098-d8c4-49f3-9900-fe3e1e4a12de" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_c2877098-d8c4-49f3-9900-fe3e1e4a12de_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_c2877098-d8c4-49f3-9900-fe3e1e4a12de" xlink:to="loc_us-gaap_EquityComponentDomain_c2877098-d8c4-49f3-9900-fe3e1e4a12de_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_21b6ea80-1346-4b86-8f62-9266cc3a4429" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_c2877098-d8c4-49f3-9900-fe3e1e4a12de" xlink:to="loc_us-gaap_EquityComponentDomain_21b6ea80-1346-4b86-8f62-9266cc3a4429" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_110e580e-5ec5-4668-9b1b-67b8d1b21d19" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_21b6ea80-1346-4b86-8f62-9266cc3a4429" xlink:to="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_110e580e-5ec5-4668-9b1b-67b8d1b21d19" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_1709e447-ebf0-42e0-b5b5-dc2387136cad" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_8846975f-5274-4714-898f-ffcb20e767a7" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_1709e447-ebf0-42e0-b5b5-dc2387136cad" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_1709e447-ebf0-42e0-b5b5-dc2387136cad_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_1709e447-ebf0-42e0-b5b5-dc2387136cad" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_1709e447-ebf0-42e0-b5b5-dc2387136cad_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_7b7c5e1e-93a6-4a43-9b1d-f6b4f2074a30" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_1709e447-ebf0-42e0-b5b5-dc2387136cad" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_7b7c5e1e-93a6-4a43-9b1d-f6b4f2074a30" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeContractMember_5e49ca8d-21a7-4146-829e-5c5bb4290534" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ForeignExchangeContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_7b7c5e1e-93a6-4a43-9b1d-f6b4f2074a30" xlink:to="loc_us-gaap_ForeignExchangeContractMember_5e49ca8d-21a7-4146-829e-5c5bb4290534" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CrossCurrencySwapContractsMember_dd06870c-5d70-4dfc-babe-8ce749b11184" xlink:href="amgn-20201231.xsd#amgn_CrossCurrencySwapContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_7b7c5e1e-93a6-4a43-9b1d-f6b4f2074a30" xlink:to="loc_amgn_CrossCurrencySwapContractsMember_dd06870c-5d70-4dfc-babe-8ce749b11184" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ForwardInterestRateContractMember_32e55c39-469d-49d1-bee1-d7e810138f6a" xlink:href="amgn-20201231.xsd#amgn_ForwardInterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_7b7c5e1e-93a6-4a43-9b1d-f6b4f2074a30" xlink:to="loc_amgn_ForwardInterestRateContractMember_32e55c39-469d-49d1-bee1-d7e810138f6a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_af1f1bf5-f4a5-43ca-808e-da1f6e2f6e52" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_7b7c5e1e-93a6-4a43-9b1d-f6b4f2074a30" xlink:to="loc_us-gaap_InterestRateSwapMember_af1f1bf5-f4a5-43ca-808e-da1f6e2f6e52" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/DerivativeinstrumentsFairValueofDerivativesDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#DerivativeinstrumentsFairValueofDerivativesDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/DerivativeinstrumentsFairValueofDerivativesDetails" xlink:type="extended" id="i716e21d3d37a427eb49145509644fb2a_DerivativeinstrumentsFairValueofDerivativesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativesFairValueLineItems_507725c2-a530-464c-8981-f0bae7a243a5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativesFairValueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_FairValuesOfBothDerivativesDesignatedAsHedgingInstrumentsAndNotDesignatedAsHedgingInstrumentsIncludedInCondensedConsolidatedBalanceSheetsAbstract_9c694f0a-c36e-44d2-bbbd-1a886ffb4750" xlink:href="amgn-20201231.xsd#amgn_FairValuesOfBothDerivativesDesignatedAsHedgingInstrumentsAndNotDesignatedAsHedgingInstrumentsIncludedInCondensedConsolidatedBalanceSheetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_507725c2-a530-464c-8981-f0bae7a243a5" xlink:to="loc_amgn_FairValuesOfBothDerivativesDesignatedAsHedgingInstrumentsAndNotDesignatedAsHedgingInstrumentsIncludedInCondensedConsolidatedBalanceSheetsAbstract_9c694f0a-c36e-44d2-bbbd-1a886ffb4750" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetFairValueNetAbstract_800fb38e-0a19-4f74-8d38-26f40fb7fdec" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeAssetFairValueNetAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amgn_FairValuesOfBothDerivativesDesignatedAsHedgingInstrumentsAndNotDesignatedAsHedgingInstrumentsIncludedInCondensedConsolidatedBalanceSheetsAbstract_9c694f0a-c36e-44d2-bbbd-1a886ffb4750" xlink:to="loc_us-gaap_DerivativeAssetFairValueNetAbstract_800fb38e-0a19-4f74-8d38-26f40fb7fdec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_ee4634b9-9d72-4a0c-aab6-a4cbe9de3828" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeAssetFairValueNetAbstract_800fb38e-0a19-4f74-8d38-26f40fb7fdec" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_ee4634b9-9d72-4a0c-aab6-a4cbe9de3828" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityFairValueNetAbstract_8274a909-64d6-444f-971e-8395f3aec672" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeLiabilityFairValueNetAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_amgn_FairValuesOfBothDerivativesDesignatedAsHedgingInstrumentsAndNotDesignatedAsHedgingInstrumentsIncludedInCondensedConsolidatedBalanceSheetsAbstract_9c694f0a-c36e-44d2-bbbd-1a886ffb4750" xlink:to="loc_us-gaap_DerivativeLiabilityFairValueNetAbstract_8274a909-64d6-444f-971e-8395f3aec672" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_a773f6f4-12c3-4229-b7e8-a9d7325f89a8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLiabilityFairValueNetAbstract_8274a909-64d6-444f-971e-8395f3aec672" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_a773f6f4-12c3-4229-b7e8-a9d7325f89a8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_b4d92f40-626e-4bc2-9c7c-aafec6c1c33a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_507725c2-a530-464c-8981-f0bae7a243a5" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_b4d92f40-626e-4bc2-9c7c-aafec6c1c33a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_30a04b9b-be5b-4916-aa59-243b1af3357e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_b4d92f40-626e-4bc2-9c7c-aafec6c1c33a" xlink:to="loc_us-gaap_HedgingDesignationAxis_30a04b9b-be5b-4916-aa59-243b1af3357e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_30a04b9b-be5b-4916-aa59-243b1af3357e_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_30a04b9b-be5b-4916-aa59-243b1af3357e" xlink:to="loc_us-gaap_HedgingDesignationDomain_30a04b9b-be5b-4916-aa59-243b1af3357e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_0ad0ac5d-770b-436f-92aa-bc0f7a9da820" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_30a04b9b-be5b-4916-aa59-243b1af3357e" xlink:to="loc_us-gaap_HedgingDesignationDomain_0ad0ac5d-770b-436f-92aa-bc0f7a9da820" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_5dba2127-449b-4d02-8dc6-d74901e1a481" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_0ad0ac5d-770b-436f-92aa-bc0f7a9da820" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_5dba2127-449b-4d02-8dc6-d74901e1a481" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_eb57eb0c-c781-4396-bef6-dfd160c0e39e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_0ad0ac5d-770b-436f-92aa-bc0f7a9da820" xlink:to="loc_us-gaap_NondesignatedMember_eb57eb0c-c781-4396-bef6-dfd160c0e39e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_9bf33905-2770-4114-9371-78a5cb699254" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_b4d92f40-626e-4bc2-9c7c-aafec6c1c33a" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_9bf33905-2770-4114-9371-78a5cb699254" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_9bf33905-2770-4114-9371-78a5cb699254_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_9bf33905-2770-4114-9371-78a5cb699254" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_9bf33905-2770-4114-9371-78a5cb699254_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_aa275bfb-7176-4d23-a441-74fb7b6e7ccc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_9bf33905-2770-4114-9371-78a5cb699254" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_aa275bfb-7176-4d23-a441-74fb7b6e7ccc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeContractMember_90165edd-50cc-4203-8c83-e73288859700" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ForeignExchangeContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_aa275bfb-7176-4d23-a441-74fb7b6e7ccc" xlink:to="loc_us-gaap_ForeignExchangeContractMember_90165edd-50cc-4203-8c83-e73288859700" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_CrossCurrencySwapContractsMember_52e6cf80-269e-4a4a-934b-e5264966e6e0" xlink:href="amgn-20201231.xsd#amgn_CrossCurrencySwapContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_aa275bfb-7176-4d23-a441-74fb7b6e7ccc" xlink:to="loc_amgn_CrossCurrencySwapContractsMember_52e6cf80-269e-4a4a-934b-e5264966e6e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_b7b67c04-64d4-448d-9f9e-1b4fcf944d87" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_aa275bfb-7176-4d23-a441-74fb7b6e7ccc" xlink:to="loc_us-gaap_InterestRateSwapMember_b7b67c04-64d4-448d-9f9e-1b4fcf944d87" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_e6d1f6d5-8d33-4021-9026-3dce3708b852" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_b4d92f40-626e-4bc2-9c7c-aafec6c1c33a" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_e6d1f6d5-8d33-4021-9026-3dce3708b852" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_e6d1f6d5-8d33-4021-9026-3dce3708b852_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_e6d1f6d5-8d33-4021-9026-3dce3708b852" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_e6d1f6d5-8d33-4021-9026-3dce3708b852_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_5a6cf0b9-cbc4-4142-911c-b03860d27717" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_e6d1f6d5-8d33-4021-9026-3dce3708b852" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_5a6cf0b9-cbc4-4142-911c-b03860d27717" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_OtherCurrentNoncurrentAssetsMember_0166a078-c013-4c72-a961-c9165e5061dc" xlink:href="amgn-20201231.xsd#amgn_OtherCurrentNoncurrentAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_5a6cf0b9-cbc4-4142-911c-b03860d27717" xlink:to="loc_amgn_OtherCurrentNoncurrentAssetsMember_0166a078-c013-4c72-a961-c9165e5061dc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_AccruedLiabilitiesOtherNonCurrentLiabilitiesMember_7da7f5dc-e33a-48f5-a829-46e8d258ffe4" xlink:href="amgn-20201231.xsd#amgn_AccruedLiabilitiesOtherNonCurrentLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_5a6cf0b9-cbc4-4142-911c-b03860d27717" xlink:to="loc_amgn_AccruedLiabilitiesOtherNonCurrentLiabilitiesMember_7da7f5dc-e33a-48f5-a829-46e8d258ffe4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCurrentAssetsMember_29c7e983-5c86-4c58-b569-44e353f6046c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherCurrentAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_5a6cf0b9-cbc4-4142-911c-b03860d27717" xlink:to="loc_us-gaap_OtherCurrentAssetsMember_29c7e983-5c86-4c58-b569-44e353f6046c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesMember_e2d28088-56db-4237-9654-4286c48a9f3c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccruedLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_5a6cf0b9-cbc4-4142-911c-b03860d27717" xlink:to="loc_us-gaap_AccruedLiabilitiesMember_e2d28088-56db-4237-9654-4286c48a9f3c" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/Contingenciesandcommitments" xlink:type="simple" xlink:href="amgn-20201231.xsd#Contingenciesandcommitments"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/Contingenciesandcommitments" xlink:type="extended" id="i936138c335b64eb5809c564515dcec0a_Contingenciesandcommitments"/>
  <link:roleRef roleURI="http://www.amgen.com/role/ContingenciesandcommitmentsTables" xlink:type="simple" xlink:href="amgn-20201231.xsd#ContingenciesandcommitmentsTables"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/ContingenciesandcommitmentsTables" xlink:type="extended" id="i17b597ff97d743759c7d19e313c86b62_ContingenciesandcommitmentsTables"/>
  <link:roleRef roleURI="http://www.amgen.com/role/ContingenciesandcommitmentsKYPROLISANDAPatentLitigationDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#ContingenciesandcommitmentsKYPROLISANDAPatentLitigationDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/ContingenciesandcommitmentsKYPROLISANDAPatentLitigationDetails" xlink:type="extended" id="i7a553599cff242bda6c57ac479f5c9c5_ContingenciesandcommitmentsKYPROLISANDAPatentLitigationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainContingenciesLineItems_cc43c9d1-63b1-44d8-9632-31a346047bce" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GainContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainContingencyPatentsAllegedlyInfringedUponNumber_886751de-873e-4d16-ba77-a431d14db92b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GainContingencyPatentsAllegedlyInfringedUponNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GainContingenciesLineItems_cc43c9d1-63b1-44d8-9632-31a346047bce" xlink:to="loc_us-gaap_GainContingencyPatentsAllegedlyInfringedUponNumber_886751de-873e-4d16-ba77-a431d14db92b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_NumberOfAssertedPatents_bb3a4e6e-b7e1-407a-95d6-c1e955c27d60" xlink:href="amgn-20201231.xsd#amgn_NumberOfAssertedPatents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GainContingenciesLineItems_cc43c9d1-63b1-44d8-9632-31a346047bce" xlink:to="loc_amgn_NumberOfAssertedPatents_bb3a4e6e-b7e1-407a-95d6-c1e955c27d60" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainContingenciesTable_cce6626b-04d7-449d-91d6-11ba6413108a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GainContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GainContingenciesLineItems_cc43c9d1-63b1-44d8-9632-31a346047bce" xlink:to="loc_us-gaap_GainContingenciesTable_cce6626b-04d7-449d-91d6-11ba6413108a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_4eb7ec8a-61f4-4092-bb39-96b984f3294c" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_GainContingenciesTable_cce6626b-04d7-449d-91d6-11ba6413108a" xlink:to="loc_srt_ConsolidatedEntitiesAxis_4eb7ec8a-61f4-4092-bb39-96b984f3294c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_4eb7ec8a-61f4-4092-bb39-96b984f3294c_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_4eb7ec8a-61f4-4092-bb39-96b984f3294c" xlink:to="loc_srt_ConsolidatedEntitiesDomain_4eb7ec8a-61f4-4092-bb39-96b984f3294c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_cdc9cdc9-70c8-4a55-b37c-b50a15b8dbb7" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_4eb7ec8a-61f4-4092-bb39-96b984f3294c" xlink:to="loc_srt_ConsolidatedEntitiesDomain_cdc9cdc9-70c8-4a55-b37c-b50a15b8dbb7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SubsidiariesMember_eab05206-5298-4fd5-8036-019f6094c116" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_cdc9cdc9-70c8-4a55-b37c-b50a15b8dbb7" xlink:to="loc_srt_SubsidiariesMember_eab05206-5298-4fd5-8036-019f6094c116" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseAxis_59a1ef7b-7546-43e6-a19f-9a4743d9904a" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_LitigationCaseAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_GainContingenciesTable_cce6626b-04d7-449d-91d6-11ba6413108a" xlink:to="loc_srt_LitigationCaseAxis_59a1ef7b-7546-43e6-a19f-9a4743d9904a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_59a1ef7b-7546-43e6-a19f-9a4743d9904a_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_LitigationCaseAxis_59a1ef7b-7546-43e6-a19f-9a4743d9904a" xlink:to="loc_srt_LitigationCaseTypeDomain_59a1ef7b-7546-43e6-a19f-9a4743d9904a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_d45ffc38-706e-4f87-9de5-5d2653ee916c" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_LitigationCaseAxis_59a1ef7b-7546-43e6-a19f-9a4743d9904a" xlink:to="loc_srt_LitigationCaseTypeDomain_d45ffc38-706e-4f87-9de5-5d2653ee916c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_KYPROLIScarfilzomibPatentLitigationMember_628177a9-f9f0-4ec9-b2dc-14c7bc07bdcc" xlink:href="amgn-20201231.xsd#amgn_KYPROLIScarfilzomibPatentLitigationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_LitigationCaseTypeDomain_d45ffc38-706e-4f87-9de5-5d2653ee916c" xlink:to="loc_amgn_KYPROLIScarfilzomibPatentLitigationMember_628177a9-f9f0-4ec9-b2dc-14c7bc07bdcc" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/ContingenciesandcommitmentsSandozPatentLitigationDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#ContingenciesandcommitmentsSandozPatentLitigationDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/ContingenciesandcommitmentsSandozPatentLitigationDetails" xlink:type="extended" id="i6bf43a590ca74ffd9c9e59c4ad43267e_ContingenciesandcommitmentsSandozPatentLitigationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainContingenciesLineItems_07f5896e-f619-4bc0-ba7b-1fe2e1b12d25" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GainContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_GainContingencyNumberofLawsuitsFiled_ecb945b9-279a-4b3e-8b52-9439518f6c5d" xlink:href="amgn-20201231.xsd#amgn_GainContingencyNumberofLawsuitsFiled"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GainContingenciesLineItems_07f5896e-f619-4bc0-ba7b-1fe2e1b12d25" xlink:to="loc_amgn_GainContingencyNumberofLawsuitsFiled_ecb945b9-279a-4b3e-8b52-9439518f6c5d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainContingenciesTable_459a394f-e8ae-4d2e-b63e-31ae784020d8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GainContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GainContingenciesLineItems_07f5896e-f619-4bc0-ba7b-1fe2e1b12d25" xlink:to="loc_us-gaap_GainContingenciesTable_459a394f-e8ae-4d2e-b63e-31ae784020d8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseAxis_6f362153-32cb-4b40-8f74-ac359c295b62" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_LitigationCaseAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_GainContingenciesTable_459a394f-e8ae-4d2e-b63e-31ae784020d8" xlink:to="loc_srt_LitigationCaseAxis_6f362153-32cb-4b40-8f74-ac359c295b62" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_6f362153-32cb-4b40-8f74-ac359c295b62_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_LitigationCaseAxis_6f362153-32cb-4b40-8f74-ac359c295b62" xlink:to="loc_srt_LitigationCaseTypeDomain_6f362153-32cb-4b40-8f74-ac359c295b62_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_ecfb8132-3f41-4a05-a13e-016ecfdfd2e7" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_LitigationCaseAxis_6f362153-32cb-4b40-8f74-ac359c295b62" xlink:to="loc_srt_LitigationCaseTypeDomain_ecfb8132-3f41-4a05-a13e-016ecfdfd2e7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_SandozIncMember_8d88b9dd-1a48-49dd-a6bf-db68357dc45e" xlink:href="amgn-20201231.xsd#amgn_SandozIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_LitigationCaseTypeDomain_ecfb8132-3f41-4a05-a13e-016ecfdfd2e7" xlink:to="loc_amgn_SandozIncMember_8d88b9dd-1a48-49dd-a6bf-db68357dc45e" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/ContingenciesandcommitmentsAmnealPharmaceuticalsLLCLitigationDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#ContingenciesandcommitmentsAmnealPharmaceuticalsLLCLitigationDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/ContingenciesandcommitmentsAmnealPharmaceuticalsLLCLitigationDetails" xlink:type="extended" id="i609a00ef2f3543fabd41b57d6cb96d9b_ContingenciesandcommitmentsAmnealPharmaceuticalsLLCLitigationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainContingenciesLineItems_1418b7e8-8d51-48d5-b9fd-256d3fae3484" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GainContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_GainContingencyNumberofLawsuitsFiled_05c423d7-4b66-4838-af97-bc9ccc95cb35" xlink:href="amgn-20201231.xsd#amgn_GainContingencyNumberofLawsuitsFiled"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GainContingenciesLineItems_1418b7e8-8d51-48d5-b9fd-256d3fae3484" xlink:to="loc_amgn_GainContingencyNumberofLawsuitsFiled_05c423d7-4b66-4838-af97-bc9ccc95cb35" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_GainContingencyNumberOfLawsuitsConsolidated_ac46a36e-1865-42dc-9b9a-95490903350c" xlink:href="amgn-20201231.xsd#amgn_GainContingencyNumberOfLawsuitsConsolidated"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GainContingenciesLineItems_1418b7e8-8d51-48d5-b9fd-256d3fae3484" xlink:to="loc_amgn_GainContingencyNumberOfLawsuitsConsolidated_ac46a36e-1865-42dc-9b9a-95490903350c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainContingenciesTable_b9832a7c-2b4a-4f1d-8fd0-8da17ed53da0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GainContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GainContingenciesLineItems_1418b7e8-8d51-48d5-b9fd-256d3fae3484" xlink:to="loc_us-gaap_GainContingenciesTable_b9832a7c-2b4a-4f1d-8fd0-8da17ed53da0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseAxis_5611bb38-8667-482f-87a2-2f89907f6b9e" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_LitigationCaseAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_GainContingenciesTable_b9832a7c-2b4a-4f1d-8fd0-8da17ed53da0" xlink:to="loc_srt_LitigationCaseAxis_5611bb38-8667-482f-87a2-2f89907f6b9e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_5611bb38-8667-482f-87a2-2f89907f6b9e_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_LitigationCaseAxis_5611bb38-8667-482f-87a2-2f89907f6b9e" xlink:to="loc_srt_LitigationCaseTypeDomain_5611bb38-8667-482f-87a2-2f89907f6b9e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_bfeee6bb-0460-496e-82af-7622a89cedff" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_LitigationCaseAxis_5611bb38-8667-482f-87a2-2f89907f6b9e" xlink:to="loc_srt_LitigationCaseTypeDomain_bfeee6bb-0460-496e-82af-7622a89cedff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_AmnealPharmaceuticalsLLCMember_d58b281d-f4cd-4af9-a3b8-9fa9feee48b7" xlink:href="amgn-20201231.xsd#amgn_AmnealPharmaceuticalsLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_LitigationCaseTypeDomain_bfeee6bb-0460-496e-82af-7622a89cedff" xlink:to="loc_amgn_AmnealPharmaceuticalsLLCMember_d58b281d-f4cd-4af9-a3b8-9fa9feee48b7" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/ContingenciesandcommitmentsImmunexandSandozLitigationDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#ContingenciesandcommitmentsImmunexandSandozLitigationDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/ContingenciesandcommitmentsImmunexandSandozLitigationDetails" xlink:type="extended" id="ieda5c2af0aed4a4fb70e6b9a8480fa60_ContingenciesandcommitmentsImmunexandSandozLitigationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsLineItems_6afc05b1-ae4d-4681-ad7f-7d49b9140f02" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherCommitmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_GainContingencyNumberofAffiliates_d2cdcc32-53f4-4acd-bc75-700f5bb6931e" xlink:href="amgn-20201231.xsd#amgn_GainContingencyNumberofAffiliates"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_6afc05b1-ae4d-4681-ad7f-7d49b9140f02" xlink:to="loc_amgn_GainContingencyNumberofAffiliates_d2cdcc32-53f4-4acd-bc75-700f5bb6931e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainContingencyPatentsAllegedlyInfringedUponNumber_7c57e8e9-5363-4b22-aae2-412167e59c67" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GainContingencyPatentsAllegedlyInfringedUponNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_6afc05b1-ae4d-4681-ad7f-7d49b9140f02" xlink:to="loc_us-gaap_GainContingencyPatentsAllegedlyInfringedUponNumber_7c57e8e9-5363-4b22-aae2-412167e59c67" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsTable_aa22ced0-682f-40b4-b006-51810662fd14" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherCommitmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_6afc05b1-ae4d-4681-ad7f-7d49b9140f02" xlink:to="loc_us-gaap_OtherCommitmentsTable_aa22ced0-682f-40b4-b006-51810662fd14" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseAxis_2d3e2f93-03db-4ee5-a8aa-59a5701022dc" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_LitigationCaseAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OtherCommitmentsTable_aa22ced0-682f-40b4-b006-51810662fd14" xlink:to="loc_srt_LitigationCaseAxis_2d3e2f93-03db-4ee5-a8aa-59a5701022dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_2d3e2f93-03db-4ee5-a8aa-59a5701022dc_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_LitigationCaseAxis_2d3e2f93-03db-4ee5-a8aa-59a5701022dc" xlink:to="loc_srt_LitigationCaseTypeDomain_2d3e2f93-03db-4ee5-a8aa-59a5701022dc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_a15fb72f-e1de-47ef-9062-da4b0c3ce820" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_LitigationCaseAxis_2d3e2f93-03db-4ee5-a8aa-59a5701022dc" xlink:to="loc_srt_LitigationCaseTypeDomain_a15fb72f-e1de-47ef-9062-da4b0c3ce820" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ImmunexAndSandozMember_be37ea8b-1f64-4b59-87a3-7bde6c2bce2f" xlink:href="amgn-20201231.xsd#amgn_ImmunexAndSandozMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_LitigationCaseTypeDomain_a15fb72f-e1de-47ef-9062-da4b0c3ce820" xlink:to="loc_amgn_ImmunexAndSandozMember_be37ea8b-1f64-4b59-87a3-7bde6c2bce2f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_ImmunexAndSamsungBioepisCoMember_c0e9d24a-ec9c-4527-b95a-8329a18812f7" xlink:href="amgn-20201231.xsd#amgn_ImmunexAndSamsungBioepisCoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_LitigationCaseTypeDomain_a15fb72f-e1de-47ef-9062-da4b0c3ce820" xlink:to="loc_amgn_ImmunexAndSamsungBioepisCoMember_c0e9d24a-ec9c-4527-b95a-8329a18812f7" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/ContingenciesandcommitmentsRepathaPatentLitigationDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#ContingenciesandcommitmentsRepathaPatentLitigationDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/ContingenciesandcommitmentsRepathaPatentLitigationDetails" xlink:type="extended" id="i09a2789d75394e45950870219fbbf6d9_ContingenciesandcommitmentsRepathaPatentLitigationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsLineItems_c3712718-cc21-4283-9024-424b4df869b4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherCommitmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainContingencyPatentsAllegedlyInfringedUponNumber_1f54155f-184b-4e42-994c-186920fd59a3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GainContingencyPatentsAllegedlyInfringedUponNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_c3712718-cc21-4283-9024-424b4df869b4" xlink:to="loc_us-gaap_GainContingencyPatentsAllegedlyInfringedUponNumber_1f54155f-184b-4e42-994c-186920fd59a3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_LitigationSettlementLengthofTrial_972ef52c-49fd-4a6e-b3ee-82d5c9b816b6" xlink:href="amgn-20201231.xsd#amgn_LitigationSettlementLengthofTrial"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_c3712718-cc21-4283-9024-424b4df869b4" xlink:to="loc_amgn_LitigationSettlementLengthofTrial_972ef52c-49fd-4a6e-b3ee-82d5c9b816b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_GainContingencyNumberOfChallenges_bb0edd5d-6ee6-4e07-afa8-71867a416a2f" xlink:href="amgn-20201231.xsd#amgn_GainContingencyNumberOfChallenges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_c3712718-cc21-4283-9024-424b4df869b4" xlink:to="loc_amgn_GainContingencyNumberOfChallenges_bb0edd5d-6ee6-4e07-afa8-71867a416a2f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsTable_39397088-25f2-43a0-bf2e-db0550cb25cc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherCommitmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_c3712718-cc21-4283-9024-424b4df869b4" xlink:to="loc_us-gaap_OtherCommitmentsTable_39397088-25f2-43a0-bf2e-db0550cb25cc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseAxis_cdcbee85-04ba-4520-b40d-102a6c3b6daf" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_LitigationCaseAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OtherCommitmentsTable_39397088-25f2-43a0-bf2e-db0550cb25cc" xlink:to="loc_srt_LitigationCaseAxis_cdcbee85-04ba-4520-b40d-102a6c3b6daf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_cdcbee85-04ba-4520-b40d-102a6c3b6daf_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_LitigationCaseAxis_cdcbee85-04ba-4520-b40d-102a6c3b6daf" xlink:to="loc_srt_LitigationCaseTypeDomain_cdcbee85-04ba-4520-b40d-102a6c3b6daf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_aac7fc0d-31a3-45ff-8d37-8b4c22e87138" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_LitigationCaseAxis_cdcbee85-04ba-4520-b40d-102a6c3b6daf" xlink:to="loc_srt_LitigationCaseTypeDomain_aac7fc0d-31a3-45ff-8d37-8b4c22e87138" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_SanofiRegeneronPatentLitigationMember_c0bd8407-afb3-4457-abf7-24d8a9704d17" xlink:href="amgn-20201231.xsd#amgn_SanofiRegeneronPatentLitigationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_LitigationCaseTypeDomain_aac7fc0d-31a3-45ff-8d37-8b4c22e87138" xlink:to="loc_amgn_SanofiRegeneronPatentLitigationMember_c0bd8407-afb3-4457-abf7-24d8a9704d17" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/ContingenciesandcommitmentsAdditionalInformationDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#ContingenciesandcommitmentsAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/ContingenciesandcommitmentsAdditionalInformationDetails" xlink:type="extended" id="ia3138473a1e3484b8116cd88ecff811a_ContingenciesandcommitmentsAdditionalInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems_84d50471-1002-468c-9d0d-0a8928c2b82e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyPendingClaimsNumber_9ca05a76-caf7-4378-a54e-89191dc4a338" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LossContingencyPendingClaimsNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_84d50471-1002-468c-9d0d-0a8928c2b82e" xlink:to="loc_us-gaap_LossContingencyPendingClaimsNumber_9ca05a76-caf7-4378-a54e-89191dc4a338" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_GainContingencyNumberOfAgreementsBreached_9cf93d3f-44e7-4f82-9ebd-17336250d38e" xlink:href="amgn-20201231.xsd#amgn_GainContingencyNumberOfAgreementsBreached"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_84d50471-1002-468c-9d0d-0a8928c2b82e" xlink:to="loc_amgn_GainContingencyNumberOfAgreementsBreached_9cf93d3f-44e7-4f82-9ebd-17336250d38e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNumberOfPlaintiffs_cea26143-3c74-4eb3-a89f-c258402deee7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LossContingencyNumberOfPlaintiffs"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_84d50471-1002-468c-9d0d-0a8928c2b82e" xlink:to="loc_us-gaap_LossContingencyNumberOfPlaintiffs_cea26143-3c74-4eb3-a89f-c258402deee7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNewClaimsFiledNumber_28046b53-c825-4e51-8e57-0f47697644a7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LossContingencyNewClaimsFiledNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_84d50471-1002-468c-9d0d-0a8928c2b82e" xlink:to="loc_us-gaap_LossContingencyNewClaimsFiledNumber_28046b53-c825-4e51-8e57-0f47697644a7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_LossContingencyNumberOfLawsuitsFiled_eb8c15a2-54d1-45d9-8e5f-78a454bdf922" xlink:href="amgn-20201231.xsd#amgn_LossContingencyNumberOfLawsuitsFiled"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_84d50471-1002-468c-9d0d-0a8928c2b82e" xlink:to="loc_amgn_LossContingencyNumberOfLawsuitsFiled_eb8c15a2-54d1-45d9-8e5f-78a454bdf922" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_LossContingencyNumberOfComplaintsStayedByTheCourt_09c4e1f4-414d-4284-b0d4-0317244db29e" xlink:href="amgn-20201231.xsd#amgn_LossContingencyNumberOfComplaintsStayedByTheCourt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_84d50471-1002-468c-9d0d-0a8928c2b82e" xlink:to="loc_amgn_LossContingencyNumberOfComplaintsStayedByTheCourt_09c4e1f4-414d-4284-b0d4-0317244db29e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable_664f9f2c-be52-4bd3-a5b5-831fd65a5e47" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LossContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_84d50471-1002-468c-9d0d-0a8928c2b82e" xlink:to="loc_us-gaap_LossContingenciesTable_664f9f2c-be52-4bd3-a5b5-831fd65a5e47" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseAxis_54cbf776-b158-44d9-95c0-bdc732dabb75" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_LitigationCaseAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_664f9f2c-be52-4bd3-a5b5-831fd65a5e47" xlink:to="loc_srt_LitigationCaseAxis_54cbf776-b158-44d9-95c0-bdc732dabb75" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_54cbf776-b158-44d9-95c0-bdc732dabb75_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_LitigationCaseAxis_54cbf776-b158-44d9-95c0-bdc732dabb75" xlink:to="loc_srt_LitigationCaseTypeDomain_54cbf776-b158-44d9-95c0-bdc732dabb75_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_0aa46260-7fdf-4694-b139-19aba72ce224" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_LitigationCaseAxis_54cbf776-b158-44d9-95c0-bdc732dabb75" xlink:to="loc_srt_LitigationCaseTypeDomain_0aa46260-7fdf-4694-b139-19aba72ce224" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_NovartisBreachOfContractActionMember_f08a5215-d78b-4ec3-ab3c-14f28f298001" xlink:href="amgn-20201231.xsd#amgn_NovartisBreachOfContractActionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_LitigationCaseTypeDomain_0aa46260-7fdf-4694-b139-19aba72ce224" xlink:to="loc_amgn_NovartisBreachOfContractActionMember_f08a5215-d78b-4ec3-ab3c-14f28f298001" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_SensiparAntitrustClassActionsMember_1c181a89-df83-4e9f-b038-262b06b92d0f" xlink:href="amgn-20201231.xsd#amgn_SensiparAntitrustClassActionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_LitigationCaseTypeDomain_0aa46260-7fdf-4694-b139-19aba72ce224" xlink:to="loc_amgn_SensiparAntitrustClassActionsMember_1c181a89-df83-4e9f-b038-262b06b92d0f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_amgn_HumiraBiosimilarAntitrustClassActionsMember_23ed992f-6119-4044-bb75-07f5a85579ec" xlink:href="amgn-20201231.xsd#amgn_HumiraBiosimilarAntitrustClassActionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_LitigationCaseTypeDomain_0aa46260-7fdf-4694-b139-19aba72ce224" xlink:to="loc_amgn_HumiraBiosimilarAntitrustClassActionsMember_23ed992f-6119-4044-bb75-07f5a85579ec" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/ContingenciesandcommitmentsUSRepatriationTaxCommitmentsDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#ContingenciesandcommitmentsUSRepatriationTaxCommitmentsDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/ContingenciesandcommitmentsUSRepatriationTaxCommitmentsDetails" xlink:type="extended" id="i7c3ae1caaa5a4c2a94a87efd8ebc10da_ContingenciesandcommitmentsUSRepatriationTaxCommitmentsDetails"/>
  <link:roleRef roleURI="http://www.amgen.com/role/Quarterlyfinancialdataunaudited" xlink:type="simple" xlink:href="amgn-20201231.xsd#Quarterlyfinancialdataunaudited"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/Quarterlyfinancialdataunaudited" xlink:type="extended" id="id02df6e8209d4b458261b15648e29ebc_Quarterlyfinancialdataunaudited"/>
  <link:roleRef roleURI="http://www.amgen.com/role/QuarterlyfinancialdataunauditedTables" xlink:type="simple" xlink:href="amgn-20201231.xsd#QuarterlyfinancialdataunauditedTables"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/QuarterlyfinancialdataunauditedTables" xlink:type="extended" id="i00f0241d705343b080dc262b3ad0a2dd_QuarterlyfinancialdataunauditedTables"/>
  <link:roleRef roleURI="http://www.amgen.com/role/QuarterlyfinancialdataunauditedDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#QuarterlyfinancialdataunauditedDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/QuarterlyfinancialdataunauditedDetails" xlink:type="extended" id="icf879be21b634780902949a8c0397863_QuarterlyfinancialdataunauditedDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectOfFourthQuarterEventsLineItems_8feda7e3-25a5-4785-8fe7-84fb8d5a620c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EffectOfFourthQuarterEventsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_3f36866f-069b-4356-9080-6e98af45eec1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EffectOfFourthQuarterEventsLineItems_8feda7e3-25a5-4785-8fe7-84fb8d5a620c" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_3f36866f-069b-4356-9080-6e98af45eec1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfit_e1205270-74c7-46ce-9909-7244872f65ef" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GrossProfit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EffectOfFourthQuarterEventsLineItems_8feda7e3-25a5-4785-8fe7-84fb8d5a620c" xlink:to="loc_us-gaap_GrossProfit_e1205270-74c7-46ce-9909-7244872f65ef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_0e01bc67-bc56-4475-bf22-7c9ee1a68aa3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EffectOfFourthQuarterEventsLineItems_8feda7e3-25a5-4785-8fe7-84fb8d5a620c" xlink:to="loc_us-gaap_NetIncomeLoss_0e01bc67-bc56-4475-bf22-7c9ee1a68aa3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_02d108d5-4050-4842-a465-03e74d349d12" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EffectOfFourthQuarterEventsLineItems_8feda7e3-25a5-4785-8fe7-84fb8d5a620c" xlink:to="loc_us-gaap_EarningsPerShareAbstract_02d108d5-4050-4842-a465-03e74d349d12" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_16511a96-7d21-4dae-a9a4-c028fec62549" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_02d108d5-4050-4842-a465-03e74d349d12" xlink:to="loc_us-gaap_EarningsPerShareBasic_16511a96-7d21-4dae-a9a4-c028fec62549" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_7fdcea0c-e532-4867-8d8b-a1251590ce53" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_02d108d5-4050-4842-a465-03e74d349d12" xlink:to="loc_us-gaap_EarningsPerShareDiluted_7fdcea0c-e532-4867-8d8b-a1251590ce53" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEffectOfFourthQuarterEventsTable_ea334402-54bc-4539-97b2-f671c9d68771" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfEffectOfFourthQuarterEventsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EffectOfFourthQuarterEventsLineItems_8feda7e3-25a5-4785-8fe7-84fb8d5a620c" xlink:to="loc_us-gaap_ScheduleOfEffectOfFourthQuarterEventsTable_ea334402-54bc-4539-97b2-f671c9d68771" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_e359c029-363e-474e-af5c-27abf06bb92a" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEffectOfFourthQuarterEventsTable_ea334402-54bc-4539-97b2-f671c9d68771" xlink:to="loc_srt_ProductOrServiceAxis_e359c029-363e-474e-af5c-27abf06bb92a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_e359c029-363e-474e-af5c-27abf06bb92a_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_e359c029-363e-474e-af5c-27abf06bb92a" xlink:to="loc_srt_ProductsAndServicesDomain_e359c029-363e-474e-af5c-27abf06bb92a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_06155f25-c3dc-484a-a238-956fa731e39a" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_e359c029-363e-474e-af5c-27abf06bb92a" xlink:to="loc_srt_ProductsAndServicesDomain_06155f25-c3dc-484a-a238-956fa731e39a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductMember_8aa9ad11-f889-461d-8f18-9e161e5c4f5b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_06155f25-c3dc-484a-a238-956fa731e39a" xlink:to="loc_us-gaap_ProductMember_8aa9ad11-f889-461d-8f18-9e161e5c4f5b" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.amgen.com/role/SCHEDULEIIVALUATIONANDQUALIFYINGACCOUNTS" xlink:type="simple" xlink:href="amgn-20201231.xsd#SCHEDULEIIVALUATIONANDQUALIFYINGACCOUNTS"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/SCHEDULEIIVALUATIONANDQUALIFYINGACCOUNTS" xlink:type="extended" id="ie5da74540eaf4068bb00d0669062e8bb_SCHEDULEIIVALUATIONANDQUALIFYINGACCOUNTS"/>
  <link:roleRef roleURI="http://www.amgen.com/role/SCHEDULEIIVALUATIONANDQUALIFYINGACCOUNTSDetails" xlink:type="simple" xlink:href="amgn-20201231.xsd#SCHEDULEIIVALUATIONANDQUALIFYINGACCOUNTSDetails"/>
  <link:definitionLink xlink:role="http://www.amgen.com/role/SCHEDULEIIVALUATIONANDQUALIFYINGACCOUNTSDetails" xlink:type="extended" id="ib75ca75bb23c484a86d51e1065fcbd76_SCHEDULEIIVALUATIONANDQUALIFYINGACCOUNTSDetails"/>
</link:linkbase>
