Via Facsimile and U.S. Mail
Mail Stop 6010


December 14, 2005


Ms. Sharon E. Tetlow
Senior Vice President, and
Chief Financial Officer
Cell Genesys Inc.
500 Forbes Boulevard
South San Francisco, CA 94080


Re:	Cell Genesys Inc.
	Form 10-K for the Fiscal Year Ended December 31, 2004
	Filed March 14, 2005
	File No. 000-19986


Dear Ms. Tetlow:

      We have limited our review of your filings to those issues
we
have addressed in our comments.  In our comments, we ask you to
provide us with information so we may better understand your
disclosure.  Please be as detailed as necessary in your
explanation.
After reviewing this information, we may raise additional
comments.

	Please understand that the purpose of our review process is
to
assist you in your compliance with the applicable disclosure
requirements and to enhance the overall disclosure in your
filings.
We look forward to working with you in these respects.  We welcome
any questions you may have about our comments or on any other
aspect
of our review.  Feel free to call us at the telephone numbers
listed
at the end of this letter.

Item 8. Consolidated Financial Statements and Supplementary Data,
page 38

Notes to Consolidated Financial Statements, page 44

1. Organization and Summary of Significant Accounting Policies,
page
44

Revenue Recognition, page 44

1. Please tell us why it is appropriate to recognize non-
refundable
upfront license fees and other payments under collaborative
agreements "based upon when the underlying development expenses
are
incurred".  In addition, as this appears to be an input-based
approach, please tell us how the input measure, the expenses, is a
reasonable surrogate for output measures.  Finally, as you
apparently
changed to this recognition method, in your Form 10-K for 2003,
from
the ratable recognition disclosed in your Form 10-K for 2002,
please
tell us whether this is a change in accounting principle, if so,
how
you have complied with APB 20 and Item 601(b)(18) of Regulation S-
K.

10. Income Taxes, page 54

2. Please tell us why it is appropriate for your accounting for
income taxes to result in you establishing accruals for certain
tax
contingencies when you apparently believe that certain positions
may
be challenged and your positions may not be fully sustained.  In
so
doing, please tell us whether you have recognized any tax benefits
for deductions that are not probable of being sustained and, if
so,
why that is appropriate under GAAP.  Please cite the authoritative
literature supporting this accounting.


       Please respond to these comments within 10 business days or
tell us when you will provide us with a response.  Please furnish
a
letter that keys your responses to our comments and provide the
requested information.  Detailed letters greatly facilitate our
review.  Please file your letter on EDGAR under the form type
label
CORRESP.

	We urge all persons who are responsible for the accuracy and
adequacy of the disclosure in the filings to be certain that the
filings include all information required under the Securities
Exchange Act of 1934 and that they have provided all information
investors require for an informed investment decision.  Since the
company and its management are in possession of all facts relating
to
a company`s disclosure, they are responsible for the accuracy and
adequacy of the disclosures they have made.

	In connection with responding to our comments, please
provide,
in your letter, a statement from the company acknowledging that:

* the company is responsible for the adequacy and accuracy of the
disclosure in the filings;

* staff comments or changes to disclosure in response to staff
comments do not foreclose the Commission from taking any action
with
respect to the filings; and

* the company may not assert staff comments as a defense in any
proceeding initiated by the Commission or any person under the
federal securities laws of the United States.

      In addition, please be advised that the Division of
Enforcement
has access to all information you provide to the staff of the
Division of Corporation Finance in our review of your filings or
in
response to our comments on your filings.

      You may contact Tabatha Akins, Staff Accountant, at (202)
551-
3658, or Oscar M. Young, Jr., Senior Accountant, at (202) 551-
3622,
if you have questions regarding the comments.  In this regard, do
not
hesitate to contact me, at (202) 551-3679.


Sincerely,



Jim B. Rosenberg
Senior Assistant Chief Accountant
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Mr. Sharon E. Tetlow
Cell Genesys Inc.
December 14, 2005
Page 3