EXHIBIT 23.1

               CONSENT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS

     We consent to the reference to our firm under the caption "Experts" in the
Post-Effective Amendment No. 1 to the Registration Statement on Form S-3 (No.
333-121732) and related Prospectus of Cell Genesys, Inc. and to the
incorporation by reference therein of our report dated January 20, 2004, with
respect to the consolidated financial statements of Cell Genesys, Inc. included
in its Annual Report (Form 10-K) for the year ended December 31, 2003, filed
with the Securities and Exchange Commission.

                                             /s/ Ernst & Young LLP

Palo Alto, California
February 11, 2005