As filed with the Securities and Exchange Commission on November 4, 1997
                                                    Registration No. 333-
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

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


                                    FORM S-8

                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                                  ZONAGEN, INC.
             (Exact name of registrant as specified in its charter)



                Delaware                                  76-0233274
    (State or other jurisdiction of                    (I.R.S. Employer
     incorporation or organization)                  Identification No.)


    2408 Timberloch Place, Suite B-4                        77380
          The Woodlands, Texas                            (Zip Code)
(Addres of Principal Executive Offices)


                  1996 NONEMPLOYEE DIRECTORS' STOCK OPTION PLAN
                            (Full title of the plan)

                               Joseph S. Podolski
                      President and Chief Executive Officer
                                  Zonagen, Inc.
                        2408 Timberloch Place, Suite B-4
                           The Woodlands, Texas 77380
                     (Name and address of agent for service)

                                 (281) 367-5892
          (Telephone number, including area code, of agent for service)

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


                                    copy to:
                                 Jeffrey L. Wade
                             Andrews & Kurth L.L.P.
                        2170 Buckthorne Place, Suite 150
                           The Woodlands, Texas 77380
                                 (713) 220-4801

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


                         CALCULATION OF REGISTRATION FEE
<TABLE>
<CAPTION>

============================================ =================== ==================================== =================
                                                                     Proposed
                                                                      Maximum      Proposed Maximum
                                                   Amount         Offering Price       Aggregate          Amount of
    Title of Securities to be Registered      to be registered     Per Share (1)  Offering Price (1)  Registration Fee
----------------------------------------------------------------------------------------------------------------------
<S>                                           <C>                     <C>            <C>                  <C>

Common Stock, par value $0.001 per share       400,000 shares         $32.56         $13,025,000          $3,947
============================================ =================== ==================================== =================
</TABLE>

(1)  Estimated  solely  for the  purpose of  calculating  the  registration  fee
     pursuant to Rule 457(c) and (h), based upon the average of the high and low
     sales prices per share of the  Registrant's  Common  Stock  reported on The
     Nasdaq       Stock       Market      on      October      30,       1997.


<PAGE>



                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT


ITEM 3.  INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE.

          Zonagen,  Inc. (the  "Company")  incorporates  herein by reference the
following  documents as of their  respective  dates as filed with the Securities
and Exchange Commission (the "Commission"):

          (a)       The Company's  Annual Report on Form 10-K (File No. 0-21198)
                    for the year  ended  December  31,  1996,  as amended by the
                    First Amendment and Second Amendment thereto on Form 10-K/A;

          (b)       The Company's  Quarterly Report on Form 10-Q for the quarter
                    ended March 31, 1997;

          (c)       The Company's  Quarterly Report on Form 10-Q for the quarter
                    ended June 30, 1997; and

          (d)       The  description  of the Company's  common stock,  par value
                    $0.001  per share (the  "Common  Stock"),  contained  in the
                    Company's  Registration Statement on Form 8-A filed with the
                    Commission  on February 2, 1993, as amended by Amendment No.
                    1 thereto filed with the Commission on February 12, 1993 and
                    Amendment No. 2 thereto  filed with the  Commission on March
                    25, 1993.

         All documents filed by the Company pursuant to Section 13(a), 13(c), 14
and 15(d) of the  Securities  Exchange Act of 1934,  as amended  (the  "Exchange
Act"), after the date of this Registration  Statement and prior to the filing of
a  post-effective  amendment which indicates that all securities  offered hereby
have been sold or which  deregisters all such  securities then 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 such documents.

ITEM 4.  DESCRIPTION OF SECURITIES.

         The  information   required  by  Item  4  is  not  applicable  to  this
Registration  Statement  because  the  class  of  securities  to be  offered  is
registered under Section 12 of the Exchange Act.

ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL.

         The  information   required  by  Item  5  is  not  applicable  to  this
Registration Statement.

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         Section 145 of the Delaware  General  Corporation  Law ("DGCL"),  inter
alia,  empowers a Delaware  corporation  to indemnify any person who was or is a
party  or is  threatened  to be  made a  party  to any  threatened,  pending  or
completed action, suit or proceeding (other than an action by or in the right of
the  corporation)  by reason of the fact that such  person is or was a director,
officer,  employee  or agent of the  corporation,  or is or was  serving  at the
request of the corporation as a director,  officer, employee or agent of another
corporation or other enterprise,  against expenses (including  attorneys' fees),
judgments, fines and amounts paid in settlement actually and reasonably incurred
by him in  connection  with such action,  suit or proceeding if he acted in good
faith and in a manner he reasonably believed to be in or not opposed to the best
interests  of the  corporation,  and,  with  respect to any  criminal  action or
proceeding, had no reasonable cause to believe his conduct was unlawful. Similar
indemnity is authorized for such persons against expenses (including  attorneys'
fees)  actually  and  reasonably  incurred  in  connection  with the  defense or
settlement of any such  threatened,  pending or completed action or suit if such
person  acted in good faith and in a manner he  reasonably  believed to be in or
not opposed to the best interests of the corporation,  and provided further that
(unless a court of competent  jurisdiction otherwise provides) such person shall
not have been adjudged liable to the corporation.  Any such  indemnification may
be made only as authorized in each specific case upon a determination by the

                                      II-2

<PAGE>



stockholders  or  disinterested  directors or by independent  legal counsel in a
written  opinion that  indemnification  is proper because the indemnitee has met
the applicable standard of conduct.

         Section 145 further  authorizes a corporation  to purchase and maintain
insurance on behalf of any person who is or was a director, officer, employee or
agent of the corporation, or is or was serving at the request of the corporation
as a director,  officer, employee or agent of another corporation or enterprise,
against  any  liability  asserted  against  him and  incurred by him in any such
capacity,  or arising out of his status as such,  whether or not the corporation
would  otherwise  have the power to indemnify him under Section 145. The Company
maintains  policies  insuring its and its  subsidiaries'  officers and directors
against  certain  liabilities  for actions taken in such  capacities,  including
liabilities under the Securities Act of 1933, as amended (the "Securities Act").

         The Company's Restated Certificate of Incorporation and Restated Bylaws
require the Company to indemnify the Company's  directors to the fullest  extent
permitted under Delaware law or any other applicable law in effect,  but if such
statute  or  law  is  amended,   the   Company   may  change  the   standard  of
indemnification  only to the extent that such amended statute or law permits the
Company to provide broader  indemnification  rights to the Company's  directors.
Pursuant to employment agreements entered into by the Company with its executive
officers  and certain  other key  employees,  the Company  must  indemnify  such
officers  and  employees  in the same  manner  and to the same  extent  that the
Company is required to indemnify its directors under its Restated Certificate of
Incorporation  and  Restated  Bylaws.  The  Company's  Restated  Certificate  of
Incorporation  limits the personal liability of a director to the Company or its
stockholders to damages for breach of the director's fiduciary duty.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.

         The  information   required  by  Item  7  is  not  applicable  to  this
Registration Statement.

Item 8.  Exhibits.


          Exhibit
          Number   Description
          ------   -----------

          4.1+      Restated  Certificate  of  Incorporation   (incorporated  by
                    reference  to  Exhibit  3.3  to the  Company's  Registration
                    Statement on Form SB-2 (No. 33-57728-FW)).

          4.2+      Certificate  of  Designation  of  the  Company's   Series  B
                    Convertible  Preferred Stock  (incorporated  by reference to
                    Exhibit 4.1 to the Company's  Quarterly  Report on Form 10-Q
                    for the quarter ended September 30, 1996).

          4.3+      Restated Bylaws (incorporated by reference to Exhibit 3.4 to
                    the  Company's  Registration  Statement  on Form  SB-2  (No.
                    33-57728-FW)).

          4.4+      Specimen Common Stock Certificate (incorporated by reference
                    to Exhibit 4.1 to the  Company's  Registration  Statement on
                    Form SB-2 (No. 33-57728-FW)).

          5.1*      Opinion of Andrews & Kurth L.L.P.

          23.1*     Consent of Andrews & Kurth L.L.P. (included in Exhibit 5.1).

          23.2*     Consent of Arthur  Andersen LLP

          24.1*     Power of Attorney (set forth on the signature page contained
                    in Part II of this Registration Statement).

          99.1+     Zonagen, Inc. 1996 Nonemployee  Directors' Stock Option Plan
                    (incorporated  by reference to Exhibit 10.1 to the Company's
                    Quarterly Report on Form 10-Q for the quarter ended June 30,
                    1997).

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

+ Incorporated herein by reference.
* Filed herewith.


                                      II-3

<PAGE>



Item 9.  Undertakings.

         (a)      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:

                              (i) To include any prospectus  required by Section
                    10(a)(3) of the Securities Act of 1933;

                              (ii) To  reflect  in the  prospectus  any facts or
                    events arising after the effective date of the  Registration
                    Statement  (or  the  most  recent  post-effective  amendment
                    thereof) which, individually or in the aggregate,  represent
                    a fundamental  change in the  information  set forth in this
                    Registration Statement;

                              (iii) 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 this Registration Statement;

         Provided,  however,  that paragraphs  (a)(1)(i) and (a)(1)(ii) above do
         not  apply  if  the   information   required   to  be   included  in  a
         post-effective  amendment by those  paragraphs is contained in periodic
         reports filed by the Company pursuant to Section 13 or Section 15(d) of
         the Securities  Exchange Act of 1934 that are incorporated by reference
         in the Registration Statement.

                  (2) That, for the purpose of determining  any liability  under
         the Securities Act of 1933, 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) The undersigned  registrant hereby undertakes that, for purposes of
determining  any liability  under the Securities Act of 1933, each filing of the
Company's  annual report  pursuant to Section  13(a) or 15(d) of the  Securities
Exchange Act of 1934 that is  incorporated  by  reference  in this  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.

         (c)  Insofar  as  indemnification  for  liabilities  arising  under the
Securities Act of 1933 may be permitted to directors,  officers and  controlling
persons of the Company pursuant to the foregoing provisions,  or otherwise,  the
Company 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 Company of expenses
incurred or paid by a director,  officer or controlling person of the Company 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 Company  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-4

<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 The  Woodlands,  Texas,  on the 31st day of October,
1997.

                                   ZONAGEN, INC.

                                    By:   /s/ Joseph S. Podolski
                                          -------------------------------
                                          Joseph S. Podolski
                                          President and Chief Executive Officer

                                POWER OF ATTORNEY

         KNOW ALL MEN BY THESE PRESENTS,  that each of the undersigned  officers
and directors of Zonagen,  Inc. (the "Company") hereby  constitutes and appoints
Joseph S.  Podolski and Louis  Ploth,  Jr., and each of them (with full power to
each of them to act alone), his true and lawful attorney-in-fact and agent, with
full power of substitution, for him and on his behalf and in his name, place and
stead, in any and all capacities,  to sign,  execute and file this  Registration
Statement  under  the  Securities  Act  of  1933,  as  amended,  and  any or all
amendments (including, without limitation,  post-effective amendments), with all
exhibits and any and all  documents  required to be filed with respect  thereto,
with  the  Securities  and  Exchange  Commission  or any  regulatory  authority,
granting unto such  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 himself  might or could do if  personally  present,  hereby
ratifying and confirming all that such  attorneys-in-fact  and agents, or any of
them, or their substitute or substitutes, may lawfully do or cause to be done.

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

<TABLE>
<CAPTION>

                 SIGNATURE                                        TITLE                               DATE
<S>                                                 <C>                                       <C>

    /s/Martin P. Sutter                             Chairman of the Board of Directors        October 31, 1997
---------------------------------------
       Martin P. Sutter

    /s/Joseph S. Podolski                       President and Chief Executive Officer and     October 31, 1997
---------------------------------------           Director (Principal Executive Officer)
       Joseph S. Podolski

    /s/Louis Ploth, Jr.                            Vice President-Business Development,       October 31, 1997
---------------------------------------
       Louis Ploth, Jr.                           Chief Financial Officer and Secretary
                                                    (Principal Accounting Officer and
                                                       Principal Financial Officer)

    /s/Steven Blasnik                                            Director                     October 31, 1997
---------------------------------------
       Steven Blasnik                                                  

    /s/James L. Currie                                           Director                     October 31, 1997
---------------------------------------
       James L. Currie

    /s/Timothy McInerney                                         Director                     October 31, 1997
---------------------------------------
       Timothy McInerney

    /s/David B. McWilliams                                       Director                     October 31, 1997
---------------------------------------
       David B. McWilliams

    /s/David W. Ortlieb                                          Director                     October 31, 1997
---------------------------------------
       David W. Ortlieb
</TABLE>
                                      II-5
[{"type": "S-8", "sequence": "1", "description": "ZONAGEN, INC. FORM S-8", "secsgml_size_bytes": 19963}]
{"company-data": {"conformed-name": "ZONAGEN INC", "cik": "0000897075", "assigned-sic": "2836", "irs-number": "760233274", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-39413", "film-number": "97707142"}, "business-address": {"street1": "2408 TIMBERLOCH PL", "street2": "B-4", "city": "WOODLANDS", "state": "TX", "zip": "77380", "phone": "2813675892"}, "mail-address": {"street1": "2408 TIMBERLOCH PLACE B-4", "city": "THE WOODLANDS", "state": "TX", "zip": "77380"}}
As filed with the Securities and Exchange Commission on November 4, 1997
                                                    Registration No. 333-
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

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

                                    FORM S-8

                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                                  ZONAGEN, INC.
             (Exact name of registrant as specified in its charter)

                Delaware                                  76-0233274
    (State or other jurisdiction of                    (I.R.S. Employer
     incorporation or organization)                  Identification No.)

    2408 Timberloch Place, Suite B-4                        77380
          The Woodlands, Texas                            (Zip Code)
(Addres of Principal Executive Offices)

                  1996 NONEMPLOYEE DIRECTORS' STOCK OPTION PLAN
                            (Full title of the plan)

                               Joseph S. Podolski
                      President and Chief Executive Officer
                                  Zonagen, Inc.
                        2408 Timberloch Place, Suite B-4
                           The Woodlands, Texas 77380
                     (Name and address of agent for service)

                                 (281) 367-5892
          (Telephone number, including area code, of agent for service)

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

                                    copy to:
                                 Jeffrey L. Wade
                             Andrews & Kurth L.L.P.
                        2170 Buckthorne Place, Suite 150
                           The Woodlands, Texas 77380
                                 (713) 220-4801

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

                         CALCULATION OF REGISTRATION FEE
============================================ =================== ==================================== =================
                                                                     Proposed
                                                                      Maximum      Proposed Maximum
                                                   Amount         Offering Price       Aggregate          Amount of
    Title of Securities to be Registered      to be registered     Per Share (1)  Offering Price (1)  Registration Fee
----------------------------------------------------------------------------------------------------------------------
Common Stock, par value $0.001 per share       400,000 shares         $32.56         $13,025,000          $3,947
============================================ =================== ==================================== =================
(1)  Estimated  solely  for the  purpose of  calculating  the  registration  fee
     pursuant to Rule 457(c) and (h), based upon the average of the high and low
     sales prices per share of the  Registrant's  Common  Stock  reported on The
     Nasdaq       Stock       Market      on      October      30,       1997.
PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE.

          Zonagen,  Inc. (the  "Company")  incorporates  herein by reference the
following  documents as of their  respective  dates as filed with the Securities
and Exchange Commission (the "Commission"):

          (a)       The Company's  Annual Report on Form 10-K (File No. 0-21198)
                    for the year  ended  December  31,  1996,  as amended by the
                    First Amendment and Second Amendment thereto on Form 10-K/A;

          (b)       The Company's  Quarterly Report on Form 10-Q for the quarter
                    ended March 31, 1997;

          (c)       The Company's  Quarterly Report on Form 10-Q for the quarter
                    ended June 30, 1997; and

          (d)       The  description  of the Company's  common stock,  par value
                    $0.001  per share (the  "Common  Stock"),  contained  in the
                    Company's  Registration Statement on Form 8-A filed with the
                    Commission  on February 2, 1993, as amended by Amendment No.
                    1 thereto filed with the Commission on February 12, 1993 and
                    Amendment No. 2 thereto  filed with the  Commission on March
                    25, 1993.

         All documents filed by the Company pursuant to Section 13(a), 13(c), 14
and 15(d) of the  Securities  Exchange Act of 1934,  as amended  (the  "Exchange
Act"), after the date of this Registration  Statement and prior to the filing of
a  post-effective  amendment which indicates that all securities  offered hereby
have been sold or which  deregisters all such  securities then 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 such documents.

ITEM 4.  DESCRIPTION OF SECURITIES.

         The  information   required  by  Item  4  is  not  applicable  to  this
Registration  Statement  because  the  class  of  securities  to be  offered  is
registered under Section 12 of the Exchange Act.

ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL.

         The  information   required  by  Item  5  is  not  applicable  to  this
Registration Statement.

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         Section 145 of the Delaware  General  Corporation  Law ("DGCL"),  inter
alia,  empowers a Delaware  corporation  to indemnify any person who was or is a
party  or is  threatened  to be  made a  party  to any  threatened,  pending  or
completed action, suit or proceeding (other than an action by or in the right of
the  corporation)  by reason of the fact that such  person is or was a director,
officer,  employee  or agent of the  corporation,  or is or was  serving  at the
request of the corporation as a director,  officer, employee or agent of another
corporation or other enterprise,  against expenses (including  attorneys' fees),
judgments, fines and amounts paid in settlement actually and reasonably incurred
by him in  connection  with such action,  suit or proceeding if he acted in good
faith and in a manner he reasonably believed to be in or not opposed to the best
interests  of the  corporation,  and,  with  respect to any  criminal  action or
proceeding, had no reasonable cause to believe his conduct was unlawful. Similar
indemnity is authorized for such persons against expenses (including  attorneys'
fees)  actually  and  reasonably  incurred  in  connection  with the  defense or
settlement of any such  threatened,  pending or completed action or suit if such
person  acted in good faith and in a manner he  reasonably  believed to be in or
not opposed to the best interests of the corporation,  and provided further that
(unless a court of competent  jurisdiction otherwise provides) such person shall
not have been adjudged liable to the corporation.  Any such  indemnification may
be made only as authorized in each specific case upon a determination by the

                                      II-2
stockholders  or  disinterested  directors or by independent  legal counsel in a
written  opinion that  indemnification  is proper because the indemnitee has met
the applicable standard of conduct.

         Section 145 further  authorizes a corporation  to purchase and maintain
insurance on behalf of any person who is or was a director, officer, employee or
agent of the corporation, or is or was serving at the request of the corporation
as a director,  officer, employee or agent of another corporation or enterprise,
against  any  liability  asserted  against  him and  incurred by him in any such
capacity,  or arising out of his status as such,  whether or not the corporation
would  otherwise  have the power to indemnify him under Section 145. The Company
maintains  policies  insuring its and its  subsidiaries'  officers and directors
against  certain  liabilities  for actions taken in such  capacities,  including
liabilities under the Securities Act of 1933, as amended (the "Securities Act").

         The Company's Restated Certificate of Incorporation and Restated Bylaws
require the Company to indemnify the Company's  directors to the fullest  extent
permitted under Delaware law or any other applicable law in effect,  but if such
statute  or  law  is  amended,   the   Company   may  change  the   standard  of
indemnification  only to the extent that such amended statute or law permits the
Company to provide broader  indemnification  rights to the Company's  directors.
Pursuant to employment agreements entered into by the Company with its executive
officers  and certain  other key  employees,  the Company  must  indemnify  such
officers  and  employees  in the same  manner  and to the same  extent  that the
Company is required to indemnify its directors under its Restated Certificate of
Incorporation  and  Restated  Bylaws.  The  Company's  Restated  Certificate  of
Incorporation  limits the personal liability of a director to the Company or its
stockholders to damages for breach of the director's fiduciary duty.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.

         The  information   required  by  Item  7  is  not  applicable  to  this
Registration Statement.

Item 8.  Exhibits.

          Exhibit
          Number   Description
          ------   -----------

          4.1+      Restated  Certificate  of  Incorporation   (incorporated  by
                    reference  to  Exhibit  3.3  to the  Company's  Registration
                    Statement on Form SB-2 (No. 33-57728-FW)).

          4.2+      Certificate  of  Designation  of  the  Company's   Series  B
                    Convertible  Preferred Stock  (incorporated  by reference to
                    Exhibit 4.1 to the Company's  Quarterly  Report on Form 10-Q
                    for the quarter ended September 30, 1996).

          4.3+      Restated Bylaws (incorporated by reference to Exhibit 3.4 to
                    the  Company's  Registration  Statement  on Form  SB-2  (No.
                    33-57728-FW)).

          4.4+      Specimen Common Stock Certificate (incorporated by reference
                    to Exhibit 4.1 to the  Company's  Registration  Statement on
                    Form SB-2 (No. 33-57728-FW)).

          5.1*      Opinion of Andrews & Kurth L.L.P.

          23.1*     Consent of Andrews & Kurth L.L.P. (included in Exhibit 5.1).

          23.2*     Consent of Arthur  Andersen LLP

          24.1*     Power of Attorney (set forth on the signature page contained
                    in Part II of this Registration Statement).

          99.1+     Zonagen, Inc. 1996 Nonemployee  Directors' Stock Option Plan
                    (incorporated  by reference to Exhibit 10.1 to the Company's
                    Quarterly Report on Form 10-Q for the quarter ended June 30,
                    1997).

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

+ Incorporated herein by reference.
* Filed herewith.

                                      II-3
Item 9.  Undertakings.

         (a)      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:

                              (i) To include any prospectus  required by Section
                    10(a)(3) of the Securities Act of 1933;

                              (ii) To  reflect  in the  prospectus  any facts or
                    events arising after the effective date of the  Registration
                    Statement  (or  the  most  recent  post-effective  amendment
                    thereof) which, individually or in the aggregate,  represent
                    a fundamental  change in the  information  set forth in this
                    Registration Statement;

                              (iii) 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 this Registration Statement;

         Provided,  however,  that paragraphs  (a)(1)(i) and (a)(1)(ii) above do
         not  apply  if  the   information   required   to  be   included  in  a
         post-effective  amendment by those  paragraphs is contained in periodic
         reports filed by the Company pursuant to Section 13 or Section 15(d) of
         the Securities  Exchange Act of 1934 that are incorporated by reference
         in the Registration Statement.

                  (2) That, for the purpose of determining  any liability  under
         the Securities Act of 1933, 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) The undersigned  registrant hereby undertakes that, for purposes of
determining  any liability  under the Securities Act of 1933, each filing of the
Company's  annual report  pursuant to Section  13(a) or 15(d) of the  Securities
Exchange Act of 1934 that is  incorporated  by  reference  in this  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.

         (c)  Insofar  as  indemnification  for  liabilities  arising  under the
Securities Act of 1933 may be permitted to directors,  officers and  controlling
persons of the Company pursuant to the foregoing provisions,  or otherwise,  the
Company 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 Company of expenses
incurred or paid by a director,  officer or controlling person of the Company 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 Company  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-4
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 The  Woodlands,  Texas,  on the 31st day of October,
1997.

                                   ZONAGEN, INC.

                                    By:   /s/ Joseph S. Podolski
                                          -------------------------------
                                          Joseph S. Podolski
                                          President and Chief Executive Officer

                                POWER OF ATTORNEY

         KNOW ALL MEN BY THESE PRESENTS,  that each of the undersigned  officers
and directors of Zonagen,  Inc. (the "Company") hereby  constitutes and appoints
Joseph S.  Podolski and Louis  Ploth,  Jr., and each of them (with full power to
each of them to act alone), his true and lawful attorney-in-fact and agent, with
full power of substitution, for him and on his behalf and in his name, place and
stead, in any and all capacities,  to sign,  execute and file this  Registration
Statement  under  the  Securities  Act  of  1933,  as  amended,  and  any or all
amendments (including, without limitation,  post-effective amendments), with all
exhibits and any and all  documents  required to be filed with respect  thereto,
with  the  Securities  and  Exchange  Commission  or any  regulatory  authority,
granting unto such  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 himself  might or could do if  personally  present,  hereby
ratifying and confirming all that such  attorneys-in-fact  and agents, or any of
them, or their substitute or substitutes, may lawfully do or cause to be done.

         Pursuant  to the  requirements  of the  Securities  Act of  1933,  this
Registration  Statement  has  been  signed  by  the  following  persons  in  the
capacities and on the dates indicated.
SIGNATURE                                        TITLE                               DATE
/s/Martin P. Sutter                             Chairman of the Board of Directors        October 31, 1997
---------------------------------------
       Martin P. Sutter

    /s/Joseph S. Podolski                       President and Chief Executive Officer and     October 31, 1997
---------------------------------------           Director (Principal Executive Officer)
       Joseph S. Podolski

    /s/Louis Ploth, Jr.                            Vice President-Business Development,       October 31, 1997
---------------------------------------
       Louis Ploth, Jr.                           Chief Financial Officer and Secretary
                                                    (Principal Accounting Officer and
                                                       Principal Financial Officer)

    /s/Steven Blasnik                                            Director                     October 31, 1997
---------------------------------------
       Steven Blasnik                                                  

    /s/James L. Currie                                           Director                     October 31, 1997
---------------------------------------
       James L. Currie

    /s/Timothy McInerney                                         Director                     October 31, 1997
---------------------------------------
       Timothy McInerney

    /s/David B. McWilliams                                       Director                     October 31, 1997
---------------------------------------
       David B. McWilliams

    /s/David W. Ortlieb                                          Director                     October 31, 1997
---------------------------------------
       David W. Ortlieb
II-5