EXHIBIT 5.1

                         [Latham & Watkins Letterhead]

                                 May 22, 2002

Amgen Inc.
One Amgen Center Drive
Thousand Oaks, California 91320-1789

   Re: $3,950,000,000 Aggregate Principal Amount at Maturity of Liquid Yield
       Option(TM) Notes due 2032 of Amgen Inc.

      Ladies and Gentlemen:

      In connection with the registration of $3,950,000,000 aggregate principal
amount at maturity of Liquid Yield Option(TM) Notes due 2032 (the "LYONs") and
the shares of common stock initially issuable upon conversion of the LYONs (the
"Common Stock" and, together with the LYONs, the "Securities") by Amgen Inc., a
Delaware corporation (the "Company"), under the Securities Act of 1933, as
amended (the "Act"), on Form S-3 filed with the Securities and Exchange
Commission to be filed on May 22, 2002 (the "Registration Statement"), you have
requested our opinion with respect to the matters set forth below.

      In our capacity as your special counsel in connection with such
registration, we are familiar with the proceedings taken and proposed to be
taken by the Company in connection with the authorization and issuance of the
Securities, and for the purposes of this opinion, have assumed such proceedings
will be timely completed in the manner presently proposed. In addition, we have
made such legal and factual examinations and inquiries, including an
examination of originals or copies certified or otherwise identified to our
satisfaction of such documents, corporate records and instruments, as we have
deemed necessary or appropriate for purposes of this opinion.

      In our examination, we have assumed the genuineness of all signatures,
the authenticity of all documents submitted to us as originals, and the
conformity to authentic original documents of all documents submitted to us as
copies.

      We are opining herein as to the effect on the subject transaction only of
the internal laws of the State of New York and the General Corporation Law of
the State of Delaware, and we express no opinion with respect to the
applicability thereto, or the effect thereon, of the laws of any other
jurisdiction or, in the case of Delaware any other laws, or as to any matters
of municipal law or the laws of any local agencies within any state.

      Capitalized terms used herein without definition have the meanings
ascribed to them in the Registration Statement.



May 22, 2002
Page 2

      Subject to the foregoing and the other matters set forth herein, it is
our opinion that as of the date hereof:

                   1. The LYONs have been duly authorized by all necessary
             corporate action of the Company, and constitute legally valid and
             binding obligations of the Company, enforceable against the
             Company in accordance with their terms.

                   2. The shares of Common Stock issuable upon conversion of
             the LYONs have been duly authorized, and when issued upon
             conversion of the LYONs in accordance with the terms of the
             Indenture, will be validly issued, fully paid and nonassessable.

      The opinions rendered in paragraph 1 relating to the enforceability of
the LYONs are subject to the following exceptions, limitations and
qualifications: (i) the effect of bankruptcy, insolvency, reorganization,
moratorium or other similar laws now or hereafter in effect relating to or
affecting the rights and remedies of creditors and (ii) the effect of general
principles of equity, whether enforcement is considered in a proceeding in
equity or law, and the discretion of the court before which any proceeding
therefor may be brought.

      In addition, we express no opinion with respect to whether acceleration
of the LYONs may affect the collectibility of that portion of the stated
principal amount thereof that might be determined to constitute unearned
interest thereon.

      We have not been requested to express, and with your knowledge and
consent, do not render any opinion as to the applicability to the obligations
of the Company under the Indenture and the LYONs under the Indenture of Section
548 of the United States Bankruptcy Code or applicable state law (including,
without limitation, Article 10 of the New York Debtor and Creditor Law)
relating to fraudulent transfers and obligations.

      To the extent that the obligations of the Company under the Indenture may
be dependent upon such matters, we assume for purposes of this opinion that the
Trustee is duly organized, validly existing and in good standing under the laws
of its jurisdiction of organization; that the Trustee is duly qualified to
engage in the activities contemplated by the Indenture; that the Indenture has
been duly authorized, executed and delivered by the Trustee and constitutes the
legally valid, binding and enforceable obligation of the Trustee enforceable
against the Trustee in accordance with its terms; that the Trustee is in
compliance, generally and with respect to acting as a trustee under the
Indenture, with all applicable laws and regulations; and that the Trustee has
the requisite organizational and legal power and authority to perform its
obligations under the Indenture.

      We consent to your filing this opinion as an exhibit to the Registration
Statement and to the reference to our firm contained under the heading
"Validity of the Securities."

                                          Very truly yours,

                                          /s/  LATHAM & WATKINS