EXHIBIT 5.1

                               OPINION OF COUNSEL

June 15, 2001


Versicor Inc.
34790 Ardentech Court
Fremont, California  94555

                  Re:     REGISTRATION STATEMENT ON FORM S-8

Ladies and Gentlemen:

         At your request, we have examined the Registration Statement on Form
S-8 (the "Registration Statement") to be filed by Versicor Inc., a Delaware
corporation (the "Company"), with the Securities and Exchange Commission in
connection with the registration under the Securities Act of 1933, as
amended, of 3,535,383 shares of the Company's Common Stock, $.001 par value
(the "Common Stock"), to be issued pursuant to the Company's 1997 Equity
Incentive Plan, as amended (the "Plan"). We have examined the proceedings
heretofore taken and to be taken in connection with the authorization of the
Plan and the Common Stock to be issued pursuant to and in accordance with the
Plan.

         Based upon such examination and upon such matters of fact and law as
we have deemed relevant, we are of the opinion that the Common Stock has been
duly authorized by all necessary corporate action on the part of the Company
and, when issued in accordance with such authorization, the provisions of the
Plan and relevant agreements duly authorized by and in accordance with the
terms of the Plan will be validly issued, fully paid and non-assessable.

         We consent to the use of this opinion as an exhibit to the
Registration Statement.

                                                   Respectfully submitted,

                                                   /s/ O'MELVENY & MYERS LLP