<PAGE>
        As filed with the Securities and Exchange Commission on August 29, 2000
                                                      Registration No. 333-
===============================================================================

                      SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C. 20549

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

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


                                SUPERGEN, INC.
            (Exact name of Registrant as specified in its charter)


           DELAWARE                                    91-1841574
(State or other jurisdiction of         (I.R.S. Employer Identification Number)
 incorporation or organization)


                           TWO ANNABEL LANE, SUITE 220
                               SAN RAMON, CA 94583
                    (Address of principal executive offices)

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

                             1993 STOCK OPTION PLAN

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

                             JOSEPH RUBINFELD, PH.D.
                             CHIEF EXECUTIVE OFFICER
                                 SUPERGEN, INC.
                           TWO ANNABEL LANE, SUITE 220
                           SAN RAMON, CALIFORNIA 94583
                                (925) 327-0200
            (Name, address and telephone number of agent for service)

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

                                    Copy to:
                               John V. Roos, Esq.
                     Wilson Sonsini Goodrich & Rosati, P.C.
                               650 Page Mill Road
                           Palo Alto, California 94304

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

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

                         CALCULATION OF REGISTRATION FEE

===============================================================================
<TABLE>
<CAPTION>
                                                                       Proposed Maximum     Proposed Maximum      Amount of
                                                     Amount to be       Offering Price          Aggregate       Registration
     Title of Securities to be Registered           Registered (1)       Per Share (2)     Offering Price (2)        Fee
------------------------------------------------- ------------------- -------------------- -------------------- --------------
<S>                                               <C>                 <C>                  <C>                  <C>
Common Stock, $.001 par value                         2,000,000           $25.03               $50,069,653.21       $13,218.39
</TABLE>

----------
(1)  Pursuant to Rule 429 of the Securities Act of 1933, as amended (the
     "Securities Act"), the prospectus delivered to participants under the
     Registrant's 1993 Stock Option Plan, as amended (the "1993 Plan"), also
     relates to an aggregate of 3,850,000 shares previously registered under
     Form S-8 Registration Nos. 333-07295, 333-58303 and 333-87369.

(2)  The Proposed Maximum Offering Price Per Share was estimated in part
     pursuant to Rule 457(h) under the Securities Act, and, in part, pursuant to
     Rule 457(c) under the Securities Act. With respect to 138,433 shares which
     are subject to outstanding options to purchase Common Stock under the 1993
     Plan, the Proposed Maximum Offering Price Per Share was estimated pursuant
     to Rule 457(h) under which Rule the per share price of options to purchase
     stock under an employee stock option plan may be estimated by reference to
     the exercise price of such options. The weighted average exercise price of
     the 138,433 subject to outstanding options under the 1993 Plan to be
     registered is $26.31. With respect to 1,861,567 shares of Common Stock
     available for future grant under the 1993 Plan, the Proposed Maximum
     Offering Price Per Share was estimated pursuant to Rule 457(c) whereby the
     per share price was determined by reference to the average between the high
     and low price reported in the Nasdaq National Market on August 23, 2000,
     which average was $24.94. The number referenced above in the table
     entitled "Proposed Maximum Offering Price per Share" represents a weighted
     average of the foregoing estimates calculated in accordance with Rules
     457(h) and 457(c).

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

<PAGE>

                                 PART II

             INFORMATION REQUIRED IN THE REGISTRATION STATEMENT


ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE

         SuperGen, Inc. (the "Company") hereby incorporates by reference in
this registration statement the following documents:

         (a) The Company's Annual Report on Form 10-K for the fiscal year
ended December 31, 1999, pursuant to Section 13 of the Securities Exchange
Act of 1934, as amended (the "Exchange Act").

         (b) The Company's Quarterly Report on Form 10-Q for the fiscal
quarter ended March 31, 2000, as amended on Form 10-Q/A filed with the
Securities and Exchange Commission (the "Commission") on May 16, 2000, and
the Company's Quarterly Report on Form 10-Q for the fiscal quarter ended June
30, 2000, each filed pursuant to Section 13 of the Exchange Act.

         (c) All other reports filed pursuant to Section 13(a) or 15(d) of
the Exchange Act since the end of the fiscal year covered by the registrant
document referred to in (a) above.

         (d) The description of the Company's Common Stock to be offered
hereby is contained in the Company's Registration Statement on Form 8-A filed
with the Commission on January 18, 1996 pursuant to Section 12(g) of the
Exchange Act, including any amendment or report filed for the purpose of
updating such description.

         All documents subsequently filed by the Company pursuant to Sections
13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to the filing of a
post-effective amendment to this registration statement which indicates that
all securities offered hereby have been sold or which deregisters all
securities remaining unsold, shall be deemed to be incorporated by reference
in this registration statement and to be a part hereof from the date of
filing of such documents.

ITEM 4.  DESCRIPTION OF SECURITIES

         Not applicable.

ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL

         Not applicable.

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS

         The Company has adopted provisions in its current Certificate of
Incorporation which (i) eliminate the personal liability of its directors to
the Company for monetary damages to the fullest extent permissible under
Delaware law; and (ii) authorize the company to indemnify its directors and
officers to the fullest extent permitted by law. Such limitation of liability
does not affect the availability of equitable remedies, such as injunctive
relief or rescission. The Company's Certificate of Incorporation also
includes a provision

                                     II-1

<PAGE>

eliminating, to the fullest extent permitted by Delaware law, the personal
liability of its directors for monetary damages for breach of fiduciary duty
as a director. In addition, the Bylaws of the Company provide that it will be
required to indemnify its officers and directors to the maximum extent and in
the manner permitted by the Delaware General Corporation Law.

         The Company has entered into separate indemnification agreements
with each of its officers, directors and key employees that contain
provisions which are in some respects broader than the specific
indemnification provisions contained in the Delaware General Corporation Law.
The indemnification agreements may require the Company, among other things,
to indemnify such officers and directors against certain liabilities that may
arise by reason of their status or service as directors or officers (other
than liabilities arising from willful misconduct of a culpable nature), to
advance their expenses incurred as a result of any proceeding against them,
as to which they could be indemnified, and to obtain director's and officer's
insurance, if available on reasonable terms. Insofar as indemnification for
liabilities arising under the Securities Act of 1933, as amended (the
"Securities Act"), may be permitted to directors, officers and controlling
persons of the Registrant pursuant to the foregoing provisions, or otherwise,
the Registrant has been advised that in the opinion of the Commission such
indemnification is against public policy as expressed in the Securities Act
and is, therefore, unenforceable.

         At present, the Company is not aware of any pending litigation
involving a director, officer, employee or agent of the Company where
indemnification will be required or permitted. The Company is not aware of
any threatened litigation or proceeding which may result in a claim for such
indemnification.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED

         Not applicable.


ITEM 8.  EXHIBITS

         4.1      1993 Stock Option Plan (as amended through July 11, 2000)

         4.2*     Form of Stock Option Agreement for use under the 1993 Stock
                  Option Plan

         5.1      Opinion of Wilson Sonsini Goodrich & Rosati, P.C., as to the
                  legality of securities being registered

         23.1     Consent of Ernst & Young LLP, Independent Auditors

         23.2     Consent of Counsel (contained in Exhibit 5.1)

         24.1     Power of Attorney (see Page II-5)

---------

 *  Incorporated by reference to the exhibit filed with the Company's
Quarterly Report on Form 10-Q filed with the Securities and Exchange
Commission on August 13, 1997.

                                     II-2

<PAGE>

ITEM 9.  UNDERTAKINGS

         (a)      RULE 415 OFFERING  The undersigned registrant hereby
undertakes:

                  (1) To file, during any period in which offers or sales are
being made, a post-effective amendment to this registration statement to
include any material information with respect to the plan of distribution not
previously disclosed in the registration statement or any material change to
such information in the registration statement.

                  (2) That, for the purpose of determining any liability
under the Securities Act, each such post-effective amendment shall be deemed
to be a new registration statement relating to the securities offered
therein, and the offering of such securities at that time shall be deemed to
be the initial bona fide offering thereof.

                  (3) To remove from registration by means of a
post-effective amendment any of the securities being registered which remain
unsold at the termination of the offering.

         (b)      FILING INCORPORATING SUBSEQUENT EXCHANGE ACT DOCUMENTS BY
REFERENCE

         The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act, each filing of the
registrant's annual report pursuant to section 13(a) or section 15(d) of the
Exchange Act (and, where applicable, each filing of an employee benefit
plan's annual report pursuant to section 15(d) of the Exchange Act) that is
incorporated by reference in the registration statement shall be deemed to be
a new registration statement relating to the securities offered therein, and
the offering of such securities at that time shall be deemed to be the
initial bona fide offering thereof.

         (h)      REQUEST FOR ACCELERATION OF EFFECTIVE DATE OR FILING OF
REGISTRATION STATEMENT ON FORM S-8

         Insofar as indemnification for liabilities arising under the
Securities Act may be permitted to directors, officers and controlling
persons of the registrant pursuant to the foregoing provisions, or otherwise,
the registrant has been advised that in the opinion of the Securities and
Exchange Commission such indemnification is against public policy as
expressed in the Act and is, therefore, unenforceable. In the event that a
claim for indemnification against such liabilities (other than the payment by
the registrant of expenses incurred or paid by a director, officer or
controlling person of the registrant in the successful defense of any action,
suit or proceeding) is asserted by such director, officer or controlling
person in connection with the securities being registered, the registrant
will, unless in the opinion of its counsel the matter has been settled by
controlling precedent, submit to a court of appropriate jurisdiction the
question whether such indemnification by it is against public policy as
expressed in the Act and will be governed by the final adjudication of such
issue.

                                     II-3

<PAGE>

                                  SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, the
Registrant 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 San Ramon, State of California, on
August 28, 2000.

                            SUPERGEN, INC.


                            By:  /s/ JOSEPH RUBINFELD
                                 -----------------------------------------------
                                 Joseph Rubinfeld, Ph.D.
                                 Chief Executive Officer, President and Director

                                     II-4

<PAGE>

                               POWER OF ATTORNEY

         KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Joseph Rubinfeld, his
attorney-in-fact, for him in any and all capacities, to sign any amendments
to this Registration Statement on Form S-8, and to file the same, with
exhibits thereto and other documents in connection therewith, with the
Securities and Exchange Commission, hereby ratifying and confirming all that
said attorney-in-fact, or his substitute or substitutes, may do or cause to
be done by virtue hereof.

         Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed below by the following persons in the
capacities and on the dates indicated.

<TABLE>
<CAPTION>

                 Signature                                             Title                                Date
-------------------------------------------      ------------------------------------------------  ----------------------
<S>                                              <C>                                               <C>

  /s/ JOSEPH RUBINFELD                           Chief Executive Officer, President and Director       August 28, 2000
-------------------------------------------      (PRINCIPAL EXECUTIVE OFFICER)
(Joseph Rubinfeld)


  /s/ RONALD H. SPAIR                            Chief Financial Officer (PRINCIPAL FINANCIAL AND      August 28, 2000
-------------------------------------------      ACCOUNTING OFFICER)
(Ronald H. Spair)


  /s/ DENIS BURGER                               Director                                              August 28, 2000
-------------------------------------------
(Denis Burger)


  /s/ THOMAS V. GIRARDI                          Director                                              August 28, 2000
-------------------------------------------
(Thomas V. Girardi)


  /s/ WALTER J. LACK                             Director                                              August 28, 2000
-------------------------------------------
(Walter J. Lack)


  /s/ JULIUS A. VIDA                             Director                                              August 28, 2000
-------------------------------------------
(Julius A. Vida)


  /s/ DANIEL ZURR                                Director                                              August 28, 2000
-------------------------------------------
(Daniel Zurr)
</TABLE>

                                     II-5

<PAGE>

                                SUPERGEN, INC.

                       REGISTRATION STATEMENT ON FORM S-8

                                EXHIBIT INDEX

<TABLE>
<CAPTION>

    Exhibit
    Number      Description
    -------     -----------
    <S>         <C>
     4.1        1993 Stock Option Plan (as amended through July 11, 2000)

     4.2*       Form of Stock Option Agreement for use under the 1993 Stock Option Plan

     5.1        Opinion of Wilson Sonsini Goodrich & Rosati, P.C., as to the
                legality of securities being registered

    23.1        Consent of Ernst & Young LLP, Independent Auditors

    23.2        Consent of Counsel (contained in Exhibit 5.1)

    24.1        Power of Attorney (see Page II-5)
</TABLE>

--------

*      Incorporated by reference to the exhibit filed with the Company's
       Quarterly Report on form 10-Q filed with the Securities and Exchange
       Commission on August 13, 1997.

                                     II-6