UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON D.C. 20549 FORM 11-K (Mark One) [X] ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2000 OR [_] TRANSITION REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 000-12477 RETIREMENT AND SAVINGS PLAN FOR AMGEN PUERTO RICO, INC. State Road 31, Kilometer 24.6, Juncos, Puerto Rico 00777 (Full title and address of the plan) AMGEN INC. (Name of issuer of the securities held) One Amgen Center Drive, Thousand Oaks, California 91320-1799 (Address of principal executive offices) (Zip Code)

The Retirement and Savings Plan for Amgen Puerto Rico, Inc. Financial Statements and Supplemental Schedule Years ended December 31, 2000 and 1999 Contents Report of Independent Auditors................................................ 1 Audited Financial Statements Statements of Net Assets Available for Benefits............................... 2 Statements of Changes in Net Assets Available for Benefits.................... 3 Notes to Financial Statements................................................. 4 Supplemental Schedule Schedule of Assets (Held at End of Year)...................................... 8

Report of Independent Auditors Amgen Puerto Rico, Inc., as Named Fiduciary, and the Plan Participants of the Retirement and Savings Plan for Amgen Puerto Rico, Inc. We have audited the accompanying statements of net assets available for benefits of The Retirement and Savings Plan for Amgen Puerto Rico, Inc. (the Plan) at December 31, 2000 and 1999, and the related statements of changes in net assets available for plan benefits for the years then ended. These financial statements are the responsibility of the Plan's management. Our responsibility is to express an opinion on these financial statements based on our audits. We conducted our audits in accordance with auditing standards generally accepted in the United States. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements. An audit also includes assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall financial statement presentation. We believe that our audits provide a reasonable basis for our opinion. In our opinion, the financial statements referred to above present fairly, in all material respects, the net assets available for benefits of the Plan at December 31, 2000 and 1999, and the changes in its net assets available for benefits for the years then ended in conformity with accounting principles generally accepted in the United States. Our audits were performed for the purpose of expressing an opinion on the financial statements taken as a whole. The accompanying supplemental schedule of assets (held at end of year) as of December 31, 2000, is presented for purpose of additional analysis and are not a required part of the basic financial statements but are supplementary information required by the Department of Labor's Rules and Regulations for Reporting and Disclosure under the Employee Retirement Income Security Act of 1974. This supplemental schedule is the responsibility of the Plan's management. This supplemental schedule has been subjected to the auditing procedures applied in our audit of the 2000 financial statements and, in our opinion, are fairly stated, in all material respects, in relation to the 2000 financial statements taken as a whole. /s/ Ernst & Young LLP April 20, 2001 San Juan, Puerto Rico Stamp No. 1692434 affixed to original of this report. -1-

The Retirement and Savings Plan for Amgen Puerto Rico, Inc. Statements of Net Assets Available for Benefits December 31 2000 1999 ----------------------------- Assets Investments at fair value $22,506,843 $21,429,514 Contributions receivable 99,401 74,680 ----------------------------- Net assets available for benefits $22,606,244 $21,504,194 ============================= See accompanying notes. -2-

The Retirement and Savings Plan for Amgen Puerto Rico, Inc. Statements of Changes in Net Assets Available for Benefits Year ended December 31 2000 1999 ------------------------------ Additions to net assets: Employee contributions $ 1,354,522 $ 1,199,051 Employer contributions 1,069,713 1,167,733 Interest and dividend income 1,002,651 698,650 Realized/unrealized gain - 6,954,298 ----------------------------- Total additions 3,426,886 10,019,732 Deductions from net assets: Benefits paid 764,867 522,588 Realized/unrealized loss 1,559,969 - ----------------------------- Total deductions 2,324,836 522,588 ----------------------------- Net increase 1,102,050 9,497,144 Net assets available for benefits at beginning of year 21,504,194 12,007,050 ----------------------------- Net assets available for benefits at end of year $22,606,244 $21,504,194 ============================= See accompanying notes. -3-

The Retirement and Savings Plan for Amgen Puerto Rico, Inc. Notes to Financial Statements December 31, 2000 1. Description of the Plan The following description of The Retirement and Savings Plan for Amgen Puerto Rico, Inc. (the Plan) provides only general information. Participants should refer to the Plan document for a more complete description of the Plan's provisions. General The Plan is a defined contribution plan covering substantially all domestic employees of Amgen Puerto Rico, Inc. (the Company). The Plan was established effective May 1, 1992 and was amended and restated effective April 1, 1996. The Plan is qualified under Section 1165(a) and (e) of the Puerto Rico Income Tax Act of 1954, as amended (the Act), and is subject to the provisions of the Employee Retirement Income Security Act of 1974 (ERISA) and Section 401(a) and (k) of the Internal Revenue Code of 1986, as amended (the Code). Contributions The Company makes contributions for all eligible employees, whether or not they have elected to make contributions to the Plan, with a Core contribution equal to 3% of each employee's eligible compensation each pay period. In addition, for employees who make contributions to the Plan, the Company makes matching contributions equal to 100% of the first 5% of the employee's eligible compensation per pay period. Participants may contribute up to 10% of their wages (a maximum of $8,000 for 2000 and 1999) to the Plan in accordance with the applicable income tax regulations. Participants may also contribute amounts representing distributions from other qualified defined benefit or defined contribution plans. Participants select the funds in which their contributions are to be invested, electing among various investment alternatives. Participants may elect for their contributions to be invested in more than one fund; however, no more than 50% of their total contributions may be invested in the Amgen Inc. Stock Fund. Participants may change their investment options at any time. Vesting Participants are immediately vested with respect to their individual contributions and earnings thereon. Participants become vested in their allocated Company matching contributions and related earnings at a rate of 25% per year for each of their first four years of service completed. The Company's Core contributions and related earnings become 100% vested upon completion of five years of service, with no partial vesting. Generally, employees must work a minimum of 1,000 hours within a Plan year to receive vesting for that year of service. Company contributions become fully vested upon attainment of normal retirement age, disability or death. -4-

The Retirement and Savings Plan for Amgen Puerto Rico, Inc. Notes to Financial Statements (continued) 1. Description of the Plan (continued) Participant Accounts Each participant's account is credited with the participant's contribution and an allocation of (a) Company contributions and (b) Plan earnings. The benefit to which a participant is entitled is the vested portion of the participant's account. Forfeited balances of terminated participants' nonvested accounts are used to reduce future Company contributions. Payment of Benefits Upon termination of service due to death, disability (as defined by the Plan) or retirement, a participant may elect to receive an amount equal to the value of the participant's vested account balance in either a lump-sum payment in cash and/or shares of Amgen Inc. common stock. The number of shares of Amgen Inc. common stock to be paid is based on quoted market value of such stock on the date the Plan is valued following employee notification. Certain restrictions apply to withdrawals of amounts from the Plan while a participant continues to be employed by the Company. Participant Loans Loans can be made to a participant generally up to 50% of the participant's vested account balance. The loans bear interest at average borrowing rates of certain major banks (ranging from 6.80% to 9.45%) and are generally payable in installments over periods ranging from one to five years. Principal and interest payments are allocated to the participant's account. Plan Termination Although it has not expressed any intent to do so, the Company has the right under the Plan to terminate the Plan subject to the provisions of ERISA. In the event of termination, participants will become 100% vested in their accounts. Trustee Banco Santander is the trustee of the Plan. 2. Summary of Significant Accounting Policies Basis of Accounting The financial statements have been prepared on the accrual basis of accounting. -5-

The Retirement and Savings Plan for Amgen Puerto Rico, Inc. Notes to Financial Statements (continued) 2. Summary of Significant Accounting Policies (continued) Reclassifications Certain amounts in the 1999 financial statements have been reclassified to conform to the 2000 presentation. Investment Income Dividend income is recognized on the ex-dividend date and interest income is recorded on an accrual basis. Unrealized gains and losses on investments are measured by the change in the difference between the fair value and cost of the securities held at the beginning and end of the period. Realized gains and losses from security transactions are recorded based on the weighted-average cost of securities sold. Investment Valuation Investments in mutual funds and Amgen Inc. common stock are valued at current market values determined through reference to public market information on the last business day of the Plan year. Participant loans are valued at their outstanding balances, which approximate fair value. Use of Estimates The preparation of the financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates. 3. Investments The fair value of individual investments that represent 5% or more of the Plan's net assets is as follows: December 31 2000 1999 ----------------------------- Amgen Inc. Stock Fund $11,229,275 $10,085,689 Fidelity Magellan Fund 3,021,450 2,826,356 Fidelity Spartan U.S. Equity Index 2,028,150 2,238,344 Fidelity OTC Portfolio 1,811,568 1,963,267 Fidelity Growth & Income Portfolio 1,160,008 1,219,038 -6-

The Retirement and Savings Plan for Amgen Puerto Rico, Inc. Notes to Financial Statements (continued) 3. Investments (continued) The Plan's investments (including gains and losses on investments bought and sold, as well as held during the year) depreciated in value by $1,559,969 in 2000 and appreciated in value by $6,954,298 in 1999 as follows: Year ended December 31 2000 1999 ------------------------------- Amgen Inc. Stock Fund $ 678,346 $5,496,131 Mutual funds (2,238,315) 1,458,167 ------------------------------- $(1,559,969) $6,954,298 =============================== 4. Income Tax Status In April 1996, the Company received a determination letter from the Puerto Rico Treasury Department that the Plan meets the requirements for qualification under the Puerto Rico Income Tax Act and the trust forming a part of the Plan is exempt from income taxes. In April 2000, the Company received a determination letter from the Internal Revenue Service stating that the Plan is qualified, in form, under Section 401(a) of the Code and, therefore, the related trust is exempt from taxation. Once qualified, the Plan is required to operate in conformity with the Act and the Code to maintain its qualification. The Company believes the Plan is being operated in compliance with the applicable requirements of the Act and the Code and, therefore, believes that the Plan is qualified and the related trust is exempt. Subsequent amendments have been structured to, and are intended to, maintain the Plan's tax qualified status. 5. Services Provided by the Company The Company provides certain administrative and recordkeeping services for the Plan at no cost to the Plan participants. In addition, the Company has paid the trustee fees and other related costs on behalf of the Plan. -7-

Supplemental Schedule The Retirement and Savings Plan for Amgen Puerto Rico, Inc. EIN: 77-0259777 Plan: 35322 Schedule H, line 4i - Schedule of Assets (Held at End of Year) December 31, 2000 Description of Current Identity of Issue Investment Value - ------------------------------------------------------------------------------------------------------------ Amgen Inc.* Common stock 174,058 shares $11,229,275 Fidelity Magellan Fund Mutual fund 25,326 shares 3,021,450 Fidelity Growth & Income Portfolio Mutual fund 27,554 shares 1,160,008 Fidelity Retirement Money Market Portfolio Money market portfolio 251,158 Fidelity Overseas Fund Mutual fund 17,193 shares 590,935 Fidelity Spartan U.S. Equity Index Mutual fund 43,327 shares 2,028,150 Fidelity Short-Term Bond Mutual fund 72,408 shares 624,158 Fidelity OTC Portfolio Mutual fund 44,131 shares 1,811,568 Fidelity Asset Manager Mutual fund 7,280 shares 122,446 Fidelity Asset Manager: Growth Mutual fund 23,602 shares 375,501 Fidelity Asset Manager: Income Mutual fund 13,290 shares 155,897 Fidelity U.S. Bond Index Portfolio Mutual fund 7,703 shares 81,584 Fidelity Contrafund Mutual fund 7,685 shares 377,864 Participant loans* Interest rates from 6.8% to 9.45% 676,849 ----------- $22,506,843 =========== *Party-in-interest -8-

SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the trustees (or other persons who administer the employee benefit plan) have duly caused this annual report to be signed on its behalf by the undersigned hereunto duly authorized. Retirement and Savings Plan for Amgen Puerto Rico, Inc. (Name of Plan) Date: 6/20/01 By: /s/ Kathryn E. Falberg ------------------ --------------------------- Kathryn E. Falberg Chief Financial Officer, Amgen Puerto Rico, Inc.

The Retirement and Savings Plan for Amgen Puerto Rico, Inc. Index to Exhibit Consent of Ernst & Young LLP, Independent Auditors Exhibit 1

EXHIBIT 1 Consent of Ernst & Young LLP, Independent Auditors We consent to the incorporation by reference in the Registration Statement (Form S-8 No. 33-47605) pertaining to The Retirement and Savings Plan for Amgen Puerto Rico, Inc. of our report dated April 20, 2001, with respect to the financial statements and supplemental schedule of The Retirement and Savings Plan for Amgen Puerto Rico, Inc. included in this Annual Report (Form 11-K) for the year ended December 31, 2000. /s/ Ernst & Young LLP San Juan, Puerto Rico June 19, 2001