<PAGE>   1
   AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON SEPTEMBER 28, 2001

                                                     REGISTRATION NO. 333-______
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                              ---------------------

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                              ---------------------

                                GERON CORPORATION
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

          DELAWARE                                             75-2287752
(State or Other Jurisdiction of                              I.R.S. Employer
Incorporation or Organization)                            Identification Number)

                              ---------------------

                             230 CONSTITUTION DRIVE
                          MENLO PARK, CALIFORNIA 94025
         (Addresses of Principal Executive Offices including Zip Codes)

                              ---------------------

                             1992 STOCK OPTION PLAN
                            (Full Title of the Plan)

                              ---------------------

          THOMAS B. OKARMA                                    COPY TO:
PRESIDENT AND CHIEF EXECUTIVE OFFICER                   ALAN C. MENDELSON, ESQ.
         GERON CORPORATION                                LATHAM & WATKINS
       230 CONSTITUTION DRIVE                          135 COMMONWEALTH DRIVE
     MENLO PARK, CALIFORNIA 94025                   MENLO PARK, CALIFORNIA 94025
          (650) 473-7700                                  (650) 328-4600
          (NAME AND ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER,
                   INCLUDING AREA CODE, OF AGENT FOR SERVICE)

                              ---------------------

<TABLE>
<CAPTION>
--------------------------------------------------------------------------------------------------------------------
                                          CALCULATION OF REGISTRATION FEE
--------------------------------------------------------------------------------------------------------------------
                                                                                     PROPOSED
                                                   AMOUNT           PROPOSED          MAXIMUM
                                                   TO BE            MAXIMUM          AGGREGATE
                                                 REGISTERED      OFFERING PRICE      OFFERING         AMOUNT OF
                                                   (1)(2)        PER SHARE (3)       PRICE (3)     REGISTRATION FEE
--------------------------------------------------------------------------------------------------------------------
<S>                                              <C>             <C>                <C>               <C>
Common Stock , $.001 par value(4)........         750,000            $ 9.48         $7,110,000        $1,777.50
--------------------------------------------------------------------------------------------------------------------
</TABLE>

(1) The 1992 Stock Option Plan (the "Plan") authorizes the issuance of 6,994,362
    shares of common stock, par value $0.001 per share, of Geron Corporation
    (the "Company") (the "Common Stock"), of which 750,000 shares are being
    registered hereunder.

(2) This Registration Statement shall also cover any additional shares of Common
    Stock which become issuable under the 1992 Stock Option Plan by reason of
    any stock dividend, stock split, recapitalization or any other similar
    transaction effected without the receipt of consideration which results in
    an increase in the number of the Registrant's outstanding shares of Common
    Stock.

(3) Estimated solely for the purposes of calculating the registration fee
    pursuant to Rule 457(h) and (c) under the Securities Act of 1933, as amended
    (the "Securities Act"), and is based on (i) the average of the high and low
    sales price of the Common Stock (GERN), as reported on The Nasdaq National
    Market on September 26, 2001 as to 750,000 shares available for future
    grants under the Plan.

(4) Each share of common stock being registered hereunder, if issued prior to
    the termination by the Company of its Rights Agreement dated as of July 20,
    2001, will include one preferred share purchase right. Prior to the
    occurrence of certain events, the preferred share purchase rights will not
    be exercisable or evidenced separately from the common stock.

================================================================================

PROPOSED SALE TO TAKE PLACE AS SOON AFTER THE EFFECTIVE DATE OF THE REGISTRATION
           STATEMENT AS OPTIONS GRANTED UNDER THE PLAN IS EXERCISED.

                                  TOTAL PAGES 7
                             EXHIBIT INDEX ON PAGE 5


<PAGE>   2

                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(A) PROSPECTUS

        The information called for in Part I of the Form S-8 is not being filed
with or included in this Form S-8 (by incorporation by reference or otherwise)
in accordance with the rules and regulations of the Securities and Exchange
Commission (the "Commission").

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

REGISTRATION OF ADDITIONAL SECURITIES

        By a Registration Statement on Form S-8 filed with the Commission on
September 23, 1996, Registration No. 333-12487, the Company initially registered
3,466,837 shares of Common Stock of the Company reserved for issuance from time
to time in connection with the Plan. By a Registration Statement on Form S-8
filed with the Commission on August 14, 1997, Registration No. 333-33635, the
Company registered an additional 800,000 shares of Common Stock of the Company
reserved for issuance from time to time in connection with the Plan. By a
Registration Statement on Form S-8 filed with the Commission on January 26,
1999, Registration No. 333-71181, the Company registered an additional 500,000
shares of Common Stock of the Company reserved for issuance from time to time in
connection with the Plan. By a Registration Statement on Form S-8 filed with the
Commission on December 23, 1999, Registration No. 333-93527, the Company
registered an additional 600,000 shares of Common Stock of the Company reserved
for issuance from time to time in connection with the Plan. By a Registration
Statement on Form S-8 filed with the Commission on September 14, 2000,
Registration No. 333-45762, the Company registered an additional 877,525 shares
of Common Stock of the Company reserved for issuance from time to time in
connection with the Plan. The Plan authorizes the issuance of 6,994,362 shares
of Common Stock. Under this Registration Statement, the Company is registering
the additional 750,000 of Common Stock issuable under the Plan. The contents of
each of the prior Registration Statements are incorporated by reference herein
to the extent not modified or superseded thereby or by any subsequently filed
document which is incorporated by reference herein or therein.

ITEM 5. EXPERTS

        The consolidated financial statements of Geron Corporation appearing in
Geron Corporation's Annual Report (Form 10-K) for the year ended December 31,
2000, have been audited by Ernst & Young LLP, independent auditors, as set forth
in their report thereon included therein and incorporated herein by reference.
Such consolidated financial statements are incorporated herein by reference in
reliance upon such report given on the authority of such firm as experts in
accounting and auditing.

ITEM 8. EXHIBITS

        See Index to Exhibits on page 5.


                                       2

<PAGE>   3

                                   SIGNATURES

        Pursuant to the requirements of the Securities Act, the Company
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Menlo Park, State of California, on September 27,
2001

                                           GERON CORPORATION


                                           By: /s/ Thomas B. Okarma
                                               ---------------------------------
                                                   Thomas B. Okarma,
                                                   President and Chief Executive
                                                   Officer
                                                   (Principal Executive Officer)


                                           By: /s/ David L. Greenwood
                                               ---------------------------------
                                                   David L. Greenwood,
                                                   Chief Financial Officer
                                                   Senior Vice President of
                                                   Corporate Development and
                                                   Treasurer
                                                   (Principal Financial and
                                                   Accounting Officer)


                                       3

<PAGE>   4

                                POWER OF ATTORNEY

        KNOW ALL MEN BY THESE PRESENT, that each person whose signature appears
below constitutes and appoints Thomas B. Okarma and David L. Greenwood, and each
of them, his true and lawful attorneys-in-fact and agents, each with full power
of substitution and resubstitution, for him and in his name, place and stead, in
any and all capacities, to sign any and all amendments (including post-effective
amendments) to this Registration Statement, and to file the same, with all
exhibits thereto and other documents in connection therewith, with the
Commission, granting unto said attorneys-in-fact and agents, and each of them,
full power and authority to do and perform each and every act and thing
requisite and necessary to be done in order to effectuate the same as fully, to
all intents and purposes, as he might or could do in person, hereby ratifying
and confirming all that each of said attorneys-in-fact and agents, or any of
them, may lawfully do or cause to be done by virtue hereof.

        Pursuant to the requirements of the Securities Act, this registration
statement has been signed by the following persons in the capacities indicated
as of September 27, 2001.


Signature                                          Title
---------                                          -----

/s/ Thomas B. Okarma            President, Chief Executive Officer and Director
---------------------------     (Principal Executive Officer)
    Thomas B. Okarma


/s/ David L. Greenwood          Chief Financial Officer, Senior Vice President
---------------------------     of Corporate Development, Treasurer (Principal
    David L. Greenwood          Financial and Accounting Officer)


/s/ Alexander E. Barkas         Director
---------------------------
    Alexander E. Barkas


/s/ Edward V. Fritzky           Director
---------------------------
    Edward V. Fritzky


/s/ Thomas D. Kiley             Director
---------------------------
    Thomas D. Kiley


/s/ Robert B. Stein             Director
---------------------------
    Robert B. Stein


/s/ John P. Walker              Director
---------------------------
    John P. Walker


/s/ Patrick J. Zenner           Director
---------------------------
    Patrick J. Zenner


                                       4

<PAGE>   5

                                INDEX TO EXHIBITS

EXHIBIT                                                                     PAGE
-------                                                                     ----
  4.1(1)    Rights Agreement dated July 20, 2001 between the Company and
            the U.S. Stock Transfer Corporation, as Rights Agent

  4.2(2)    Registration Rights Agreement dated March 27, 1998, among
            the Registrant Certain Investors

  4.3(3)    Registration Rights Agreement dated as of December 10, 1998
            among the Registrant and certain investors

  4.4(4)    Registration Rights Agreement, dated April 30, 1999, by and
            among the Registrant and each of the Shareholders of Roslin

  4.5(5)    Registration Rights Agreement dated as of September 30, 1999
            by and between the Registrant and RGC International
            Investors, LDC

  4.6(6)    Form of Warrant

  4.7(7)    Form of Debenture

  5.1       Opinion of Latham & Watkins                                      6

 23.1       Consent of Latham & Watkins (included in Exhibit 5.1)            6

 23.2       Consent of Ernst & Young LLP, Independent Auditors               7

 24.1       Powers of Attorney                                               4

-----------------
(1) Incorporated by reference to Exhibit 4.1 of the Registrant's Current Report
    on Form 8-K filed on July 23, 2001.

(2) Incorporated by reference to Exhibit 10.39 of the Registrant's Current
    Report on Form 8-K filed on April 2, 1998.

(3) Incorporated by reference to Exhibit 10.41 of the Registrant's Current
    Report on Form 8-K filed on December 17, 1998.

(4) Incorporated by reference to Exhibit 4.1 of the Registrant's Current Report
    on Form 8-K filed on May 18, 1999.

(5) Incorporated by reference to Exhibit 99.2 of the Registrant's Current Report
    on Form 8-K filed on October 7, 1999.

(6) Incorporated by reference to Exhibit 4.2 of the Registrant's Current Report
    on Form 8-K filed on December 17, 1998.

(7) Incorporated by reference to Exhibit 4.1 of the Registrant's Current Report
    on Form 8-K filed on December 17, 1998.


                                       5
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{"company-data": {"conformed-name": "GERON CORPORATION", "cik": "0000886744", "assigned-sic": "2834", "irs-number": "752287752", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-70414", "film-number": "1747686"}, "business-address": {"street1": "230 CONSTITUTION DRIVE", "city": "MENLO PARK", "state": "CA", "zip": "94025", "phone": "6504737700"}, "mail-address": {"street1": "200 CONSTITUTION DRIVE", "city": "MENLO PARK", "state": "CA", "zip": "94025"}}
1
   AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON SEPTEMBER 28, 2001

                                                     REGISTRATION NO. 333-______
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                              ---------------------

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                              ---------------------

                                GERON CORPORATION
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

          DELAWARE                                             75-2287752
(State or Other Jurisdiction of                              I.R.S. Employer
Incorporation or Organization)                            Identification Number)

                              ---------------------

                             230 CONSTITUTION DRIVE
                          MENLO PARK, CALIFORNIA 94025
         (Addresses of Principal Executive Offices including Zip Codes)

                              ---------------------

                             1992 STOCK OPTION PLAN
                            (Full Title of the Plan)

                              ---------------------

          THOMAS B. OKARMA                                    COPY TO:
PRESIDENT AND CHIEF EXECUTIVE OFFICER                   ALAN C. MENDELSON, ESQ.
         GERON CORPORATION                                LATHAM & WATKINS
       230 CONSTITUTION DRIVE                          135 COMMONWEALTH DRIVE
     MENLO PARK, CALIFORNIA 94025                   MENLO PARK, CALIFORNIA 94025
          (650) 473-7700                                  (650) 328-4600
          (NAME AND ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER,
                   INCLUDING AREA CODE, OF AGENT FOR SERVICE)

                              ---------------------
--------------------------------------------------------------------------------------------------------------------
                                          CALCULATION OF REGISTRATION FEE
--------------------------------------------------------------------------------------------------------------------
                                                                                     PROPOSED
                                                   AMOUNT           PROPOSED          MAXIMUM
                                                   TO BE            MAXIMUM          AGGREGATE
                                                 REGISTERED      OFFERING PRICE      OFFERING         AMOUNT OF
                                                   (1)(2)        PER SHARE (3)       PRICE (3)     REGISTRATION FEE
--------------------------------------------------------------------------------------------------------------------
Common Stock , $.001 par value(4)........         750,000            $ 9.48         $7,110,000        $1,777.50
--------------------------------------------------------------------------------------------------------------------
(1) The 1992 Stock Option Plan (the "Plan") authorizes the issuance of 6,994,362
    shares of common stock, par value $0.001 per share, of Geron Corporation
    (the "Company") (the "Common Stock"), of which 750,000 shares are being
    registered hereunder.

(2) This Registration Statement shall also cover any additional shares of Common
    Stock which become issuable under the 1992 Stock Option Plan by reason of
    any stock dividend, stock split, recapitalization or any other similar
    transaction effected without the receipt of consideration which results in
    an increase in the number of the Registrant's outstanding shares of Common
    Stock.

(3) Estimated solely for the purposes of calculating the registration fee
    pursuant to Rule 457(h) and (c) under the Securities Act of 1933, as amended
    (the "Securities Act"), and is based on (i) the average of the high and low
    sales price of the Common Stock (GERN), as reported on The Nasdaq National
    Market on September 26, 2001 as to 750,000 shares available for future
    grants under the Plan.

(4) Each share of common stock being registered hereunder, if issued prior to
    the termination by the Company of its Rights Agreement dated as of July 20,
    2001, will include one preferred share purchase right. Prior to the
    occurrence of certain events, the preferred share purchase rights will not
    be exercisable or evidenced separately from the common stock.

================================================================================

PROPOSED SALE TO TAKE PLACE AS SOON AFTER THE EFFECTIVE DATE OF THE REGISTRATION
           STATEMENT AS OPTIONS GRANTED UNDER THE PLAN IS EXERCISED.

                                  TOTAL PAGES 7
                             EXHIBIT INDEX ON PAGE 5
2

                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(A) PROSPECTUS

        The information called for in Part I of the Form S-8 is not being filed
with or included in this Form S-8 (by incorporation by reference or otherwise)
in accordance with the rules and regulations of the Securities and Exchange
Commission (the "Commission").

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

REGISTRATION OF ADDITIONAL SECURITIES

        By a Registration Statement on Form S-8 filed with the Commission on
September 23, 1996, Registration No. 333-12487, the Company initially registered
3,466,837 shares of Common Stock of the Company reserved for issuance from time
to time in connection with the Plan. By a Registration Statement on Form S-8
filed with the Commission on August 14, 1997, Registration No. 333-33635, the
Company registered an additional 800,000 shares of Common Stock of the Company
reserved for issuance from time to time in connection with the Plan. By a
Registration Statement on Form S-8 filed with the Commission on January 26,
1999, Registration No. 333-71181, the Company registered an additional 500,000
shares of Common Stock of the Company reserved for issuance from time to time in
connection with the Plan. By a Registration Statement on Form S-8 filed with the
Commission on December 23, 1999, Registration No. 333-93527, the Company
registered an additional 600,000 shares of Common Stock of the Company reserved
for issuance from time to time in connection with the Plan. By a Registration
Statement on Form S-8 filed with the Commission on September 14, 2000,
Registration No. 333-45762, the Company registered an additional 877,525 shares
of Common Stock of the Company reserved for issuance from time to time in
connection with the Plan. The Plan authorizes the issuance of 6,994,362 shares
of Common Stock. Under this Registration Statement, the Company is registering
the additional 750,000 of Common Stock issuable under the Plan. The contents of
each of the prior Registration Statements are incorporated by reference herein
to the extent not modified or superseded thereby or by any subsequently filed
document which is incorporated by reference herein or therein.

ITEM 5. EXPERTS

        The consolidated financial statements of Geron Corporation appearing in
Geron Corporation's Annual Report (Form 10-K) for the year ended December 31,
2000, have been audited by Ernst & Young LLP, independent auditors, as set forth
in their report thereon included therein and incorporated herein by reference.
Such consolidated financial statements are incorporated herein by reference in
reliance upon such report given on the authority of such firm as experts in
accounting and auditing.

ITEM 8. EXHIBITS

        See Index to Exhibits on page 5.

                                       2
3

                                   SIGNATURES

        Pursuant to the requirements of the Securities Act, the Company
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Menlo Park, State of California, on September 27,
2001

                                           GERON CORPORATION

                                           By: /s/ Thomas B. Okarma
                                               ---------------------------------
                                                   Thomas B. Okarma,
                                                   President and Chief Executive
                                                   Officer
                                                   (Principal Executive Officer)

                                           By: /s/ David L. Greenwood
                                               ---------------------------------
                                                   David L. Greenwood,
                                                   Chief Financial Officer
                                                   Senior Vice President of
                                                   Corporate Development and
                                                   Treasurer
                                                   (Principal Financial and
                                                   Accounting Officer)

                                       3
4

                                POWER OF ATTORNEY

        KNOW ALL MEN BY THESE PRESENT, that each person whose signature appears
below constitutes and appoints Thomas B. Okarma and David L. Greenwood, and each
of them, his true and lawful attorneys-in-fact and agents, each with full power
of substitution and resubstitution, for him and in his name, place and stead, in
any and all capacities, to sign any and all amendments (including post-effective
amendments) to this Registration Statement, and to file the same, with all
exhibits thereto and other documents in connection therewith, with the
Commission, granting unto said attorneys-in-fact and agents, and each of them,
full power and authority to do and perform each and every act and thing
requisite and necessary to be done in order to effectuate the same as fully, to
all intents and purposes, as he might or could do in person, hereby ratifying
and confirming all that each of said attorneys-in-fact and agents, or any of
them, may lawfully do or cause to be done by virtue hereof.

        Pursuant to the requirements of the Securities Act, this registration
statement has been signed by the following persons in the capacities indicated
as of September 27, 2001.

Signature                                          Title
---------                                          -----

/s/ Thomas B. Okarma            President, Chief Executive Officer and Director
---------------------------     (Principal Executive Officer)
    Thomas B. Okarma

/s/ David L. Greenwood          Chief Financial Officer, Senior Vice President
---------------------------     of Corporate Development, Treasurer (Principal
    David L. Greenwood          Financial and Accounting Officer)

/s/ Alexander E. Barkas         Director
---------------------------
    Alexander E. Barkas

/s/ Edward V. Fritzky           Director
---------------------------
    Edward V. Fritzky

/s/ Thomas D. Kiley             Director
---------------------------
    Thomas D. Kiley

/s/ Robert B. Stein             Director
---------------------------
    Robert B. Stein

/s/ John P. Walker              Director
---------------------------
    John P. Walker

/s/ Patrick J. Zenner           Director
---------------------------
    Patrick J. Zenner

                                       4
5

                                INDEX TO EXHIBITS

EXHIBIT                                                                     PAGE
-------                                                                     ----
  4.1(1)    Rights Agreement dated July 20, 2001 between the Company and
            the U.S. Stock Transfer Corporation, as Rights Agent

  4.2(2)    Registration Rights Agreement dated March 27, 1998, among
            the Registrant Certain Investors

  4.3(3)    Registration Rights Agreement dated as of December 10, 1998
            among the Registrant and certain investors

  4.4(4)    Registration Rights Agreement, dated April 30, 1999, by and
            among the Registrant and each of the Shareholders of Roslin

  4.5(5)    Registration Rights Agreement dated as of September 30, 1999
            by and between the Registrant and RGC International
            Investors, LDC

  4.6(6)    Form of Warrant

  4.7(7)    Form of Debenture

  5.1       Opinion of Latham & Watkins                                      6

 23.1       Consent of Latham & Watkins (included in Exhibit 5.1)            6

 23.2       Consent of Ernst & Young LLP, Independent Auditors               7

 24.1       Powers of Attorney                                               4

-----------------
(1) Incorporated by reference to Exhibit 4.1 of the Registrant's Current Report
    on Form 8-K filed on July 23, 2001.

(2) Incorporated by reference to Exhibit 10.39 of the Registrant's Current
    Report on Form 8-K filed on April 2, 1998.

(3) Incorporated by reference to Exhibit 10.41 of the Registrant's Current
    Report on Form 8-K filed on December 17, 1998.

(4) Incorporated by reference to Exhibit 4.1 of the Registrant's Current Report
    on Form 8-K filed on May 18, 1999.

(5) Incorporated by reference to Exhibit 99.2 of the Registrant's Current Report
    on Form 8-K filed on October 7, 1999.

(6) Incorporated by reference to Exhibit 4.2 of the Registrant's Current Report
    on Form 8-K filed on December 17, 1998.

(7) Incorporated by reference to Exhibit 4.1 of the Registrant's Current Report
    on Form 8-K filed on December 17, 1998.

                                       5