Opinion Letter – Outside Counsel – S-3 Registered Securities – Amgen Inc.

November 10, 2011
Amgen Inc. One Amgen Center Drive Thousand Oaks, CA 91320

Re:

Registration Statement No. 333-172617; $1,000,000,000 Aggregate Principal

Amount of 1.875% Senior Notes due 2014, $1,000,000,000 Aggregate
Principal

Amount of 2.50% Senior Notes due 2016, $1,750,000,000 Aggregate
Principal

Amount of 3.875% Senior Notes due 2021 and $2,250,000,000 Aggregate

Principal Amount of 5.15% Senior Notes due 2041

Ladies and Gentlemen:

We have acted as special counsel to Amgen Inc., a Delaware corporation (the
“Company“), in connection with the issuance of
$1,000,000,000 aggregate principal amount of 1.875% Senior Notes due 2014 (the
“2014 Notes“), $1,000,000,000 aggregate principal
amount of 2.50% Senior Notes due 2016 (the “2016
Notes“), $1,750,000,000 aggregate principal amount of 3.875%
Senior Notes due 2021 (the “2021 Notes“) and
$2,250,000,000 aggregate principal amount of 5.15% Senior Notes due 2041 (the
“2041 Notes” and, together with the 2014 Notes, the
2016 Notes and the 2021 Notes, the “Notes“), under an
Indenture, dated as of August 4, 2003 (the
“Indenture“), between the Company and The Bank of New
York Mellon (as successor to JPMorgan Chase Bank, N.A.), as trustee (the
“Trustee“), and an officers’ certificate, dated
November 10, 2011, setting forth the terms of the Notes (the
“Officers’ Certificate“), and pursuant to a
registration statement on Form S-3 under the Securities Act of 1933, as amended
(the “Act“), filed with the Securities and Exchange
Commission (the “Commission“) on March 4, 2011
(Registration No. 333-172617) (the “Registration
Statement“), a base prospectus dated March 4, 2011, included in
the Registration Statement at the time it originally became effective (the
“Base Prospectus“), a final prospectus supplement,
dated November 7, 2011, filed with the Commission pursuant to Rule 424(b) under
the Act on November 8, 2011 (together with the Base Prospectus, the
“Prospectus“) and an underwriting agreement, dated
November 7, 2011, between the underwriters named therein and the Company (the
“Underwriting Agreement“).

This opinion is being furnished in connection with the requirements of Item
601(b)(5) of Regulation S-K under the Act, and no opinion is expressed herein as
to any matter pertaining to the contents of the Registration Statement or
related prospectus, other than as expressly stated herein with respect to the
issuance of the Notes.

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November 10, 2011

Page 2

As such counsel, we have examined such matters of fact and questions of law
as we have considered appropriate for purposes of this letter. With your
consent, we have relied upon certificates and other assurances of officers of
the Company and others as to factual matters without having independently
verified such factual matters. We are opining herein as to 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.

Subject to the foregoing and the other matters set forth herein, it is our
opinion that, as of the date hereof, the Notes have been duly authorized by all
necessary corporate action of the Company and, when the Notes have been duly
executed, issued, and authenticated in accordance with the terms of the
Indenture and delivered against payment therefore in the circumstances
contemplated by the Underwriting Agreement, will be legally valid and binding
obligations of the Company enforceable against the Company in accordance with
their terms.

Our opinion is subject to: (i) the effect of bankruptcy, insolvency,
reorganization, fraudulent transfer, moratorium or other similar laws relating
to or affecting the rights and remedies of creditors; (ii) the effect of general
principles of equity, whether enforcement is considered in a proceeding in
equity or at law (including the possible unavailability of specific performance
or injunctive relief), concepts of materiality, reasonableness, good faith and
fair dealing, and the discretion of the court before which any proceeding
therefore may be brought; (iii) the invalidity under certain circumstances under
law or court decisions of provisions providing for the indemnification of or
contribution to a party with respect to a liability where such indemnification
or contribution is contrary to public policy; and (iv) we express no opinion as
to (a) any provision for liquidated damages, default interest, late charges,
monetary penalties, make-whole premiums or other economic remedies to the extent
such provisions are deemed to constitute a penalty; (b) consents to, or
restrictions upon, governing law, jurisdiction, venue, arbitration, remedies or
judicial relief; (c) the waiver of rights or defenses contained in Section 4.4
of the Indenture; (d) any provision requiring the payment of attorneys’ fees,
where such payment is contrary to law or public policy; (e) advance waivers of
claims, defenses, rights granted by law, or notice, opportunity for hearing,
evidentiary requirements, statutes of limitation, trial by jury or at law or
other procedural rights; (f) waivers of broadly or vaguely stated rights; (g)
provisions for exclusivity, election or cumulation of rights or remedies; (h)
provisions authorizing or validating conclusive or discretionary determinations;
(i) grants of setoff rights; (j) proxies, powers and trusts; (k) provisions
prohibiting, restricting or requiring consent to assignment or transfer of any
right or property; and (l) the severability, if invalid, of provisions to the
foregoing effect.

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November 10, 2011

Page 3

With your consent, we have assumed (a) that the Indenture, the Officers’
Certificate and the Notes (collectively, the
“Documents“) have been duly authorized, executed and
delivered by the parties thereto other than the Company, (b) that the Documents
constitute legally valid and binding obligations of the parties thereto other
than the Company, enforceable against each of them in accordance with their
respective terms, and (c) that the status of the Documents as legally valid and
binding obligations of the parties is not affected by any (i) breaches of, or
defaults under, agreements or instruments, (ii) violations of statutes, rules,
regulations or court or governmental orders, or (iii) failures to obtain
required consents, approvals or authorizations from, or make required
registrations, declarations or filings with, governmental authorities.

This opinion is for your benefit in connection with the Registration
Statement and may be relied upon by you and by persons entitled to rely upon it
pursuant to the applicable provisions of the Act. We consent to your filing this
opinion as an exhibit to the Company’s Form 8-K dated November 10, 2011 and to
the reference to our firm contained in the Prospectus under the heading
“Validity of the Notes.” In giving such consent, we do not thereby admit that we
are in the category of persons whose consent is required under Section 7 of the
Act or the rules and regulations of the Commission thereunder.

Very truly yours,

/s/ Latham & Watkins LLP