EXHIBIT 32.2

                            CERTIFICATION PURSUANT TO
                             18 U.S.C. SECTION 1350,
                             AS ADOPTED PURSUANT TO
                  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

         Pursuant to 18 U.S.C. Section 1350, as created by Section 906 of the
Sarbanes-Oxley Act of 2002, the undersigned officer of Geron Corporation (the
"Company") hereby certifies, to such officer's knowledge, that:

    (i)  the accompanying Quarterly Report on Form 10-Q of the Company for the
         three months ended June 30, 2003 (the "Report") fully complies with the
         requirements of Section 13(a) or Section 15(d), as applicable, of the
         Securities Exchange Act of 1934, as amended; and

    (ii) the information contained in the Report fairly presents, in all
         material respects, the financial condition and results of operations of
         the Company.

Dated: July 30, 2003                /s/ David L. Greenwood
                                    --------------------------------------------
                                    David L. Greenwood
                                    Senior Vice President, Corporate Development
                                    and Chief Financial Officer

A signed original of this written statement required by Section 906 has been
provided to Geron Corporation and will be retained by Geron Corporation and
furnished to the Securities and Exchange Commission or its staff upon request.