<PAGE>
[COOLEY GODWARD LLP LETTERHEAD]
EXHIBIT 5.1
October 30, 2000
Exelixis, Inc.
170 Harbor Way
P.O. Box 511
South San Francisco, CA 94083
Ladies and Gentlemen:
We have acted as counsel for Exelixis, Inc., a Delaware corporation (the
"Company") in connection with the merger (the "Merger") contemplated by that
certain Agreement and Plan of Merger and Reorganization, dated as of
September 7, 2000, by and among the Company, Athens Acquisition Corp., a
Delaware corporation and a wholly-owned subsidiary of the Company, and
Agritope, Inc., a Delaware corporation ("Agritope"). This opinion is being
furnished in connection with the Registration Statement on Form S-4 (No.
333-47710), as amended (the "Registration Statement"), which covers a total of
up to 2,612,764 shares of the Company's common stock, par value $.001 per share
(the "Common Stock"), to be issued in connection with the Merger.
In rendering this opinion, we have examined the following documents:
(i) the Company's Amended and Restated Certificate of Incorporation and Restated
Bylaws, (ii) the resolutions adopted by the Board of Directors of the Company on
September 7, 2000, (iii) the Registration Statement and (iv) such other
documents, legal opinions and precedents, corporate and other records of the
Company and certificates of public officials and officers of the Company that we
have deemed necessary or appropriate to provide a basis for the below opinion.
Based upon and subject to the foregoing, in our opinion, the shares of
Common Stock of the Company which are being offered and sold by the Company
pursuant to the Registration Statement, when sold in the manner and for the
consideration contemplated by the Registration Statement, will be legally
issued, fully paid and non-assessable.
We consent to the filing of this opinion as an Exhibit to the Registration
Statement and to the reference to our firm under the heading "Legal Matters."
Very truly yours,
Cooley Godward LLP
/s/ Suzanne Sawochka Hooper
Suzanne Sawochka Hooper
