SC TO-C

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549


                                   SCHEDULE TO
                                  (RULE 13E-4)

   TENDER OFFER STATEMENT UNDER SECTION 14(D)(1) OR 13(E)(1) OF THE SECURITIES
                              EXCHANGE ACT OF 1934

                                  ZONAGEN, INC.
                    ---------------------------------------
                       (NAME OF SUBJECT COMPANY (ISSUER))


                                  ZONAGEN, INC.
                    ---------------------------------------
                 (Names of Filing Persons (offeror and issuer))

                    Common Stock, par value $0.001 per share
                    ----------------------------------------
                         (Title of Class of Securities)

                                   98975L 10 8
                                   -----------
                      (CUSIP Number of Class of Securities)

                               Joseph S. Podolski
                      President and Chief Executive Officer
                                  Zonagen, Inc.
                        2408 Timberloch Place, Suite B-10
                           The Woodlands, Texas 77380
                                 (281) 719-3400
                    (Name, address, and telephone numbers of
                    person authorized to receive notices and
                   communications on behalf of filing persons)

                                    Copy to:

                                Jeffrey R. Harder
                                Andrews Kurth LLP
                     10001 Woodloch Forest Drive, Suite 200
                           The Woodlands, Texas 77380
                                 (713) 220-4801

|X| Check the box if the filing relates solely to preliminary communications
    made before the commencement of a tender offer.

Check the appropriate boxes below to designate any transactions to which the
statement relates:

                  [ ] third-party tender offer subject to Rule 14d-1.
                  [X] issuer tender offer subject to Rule 13e-4.
                  [X] going-private transaction subject to Rule 13e-3.
                  [ ] amendment to Schedule 13D under Rule 13d-2.

Check the following box if the filing is a final amendment reporting results of
the tender offer: [ ]



ITEM 12.          EXHIBITS.

         (a)(1)      Press Release Issued on October 17, 2003 Announcing
                     Proposed Tender Offer.


                                       2



                                  EXHIBIT INDEX


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

  (a)(1)           Press Release Issued on October 17, 2003 Announcing Proposed
                   Tender Offer.


                                       3

EX-99.A1

                                                                 EXHIBIT (a)(1)

Contact:
Joe Podolski, President and CEO
podolski@zonagen.com
281-719-3447


FOR IMMEDIATE RELEASE


             ZONAGEN ANNOUNCES PROPOSED "DUTCH AUCTION" TENDER OFFER

         (The Woodlands, Texas) - October 17, 2003 - Zonagen, Inc. ("Zonagen")
(NASDAQ: ZONA) announced today that its Board of Directors has approved a "Dutch
Auction" tender offer to purchase up to 9,836,065 shares of its outstanding
common stock at a purchase price per share no greater than $2.10 nor less than
$1.83. Zonagen will pay no more than an aggregate of $18 million for all
tendered shares, which will result in Zonagen retaining approximately $4 million
in cash or more following the proposed tender offer. Under the terms of the
proposed offer, Zonagen will select the lowest purchase price that will allow it
to purchase the lesser of (1) all of the shares tendered prior to the expiration
date or (2) a number of shares with an aggregate purchase price of $18 million.
If more shares are tendered than Zonagen can purchase for an aggregate purchase
price of $18 million, Zonagen will first purchase all of the shares held by
stockholders holding less than 1,000 shares and will then purchase the remaining
shares on a pro rata basis.

         The offer is subject to, among other things, at least 30% of the shares
being tendered. The offer will be subject to a number of additional terms and
conditions, which will be detailed in an Offer to Purchase that will be mailed
to all stockholders as soon as reasonably practicable after this announcement.
The Offer to Purchase will also describe Zonagen's plans after the completion of
the tender offer. The Company urges stockholders to read that document
carefully.

         Zonagen has actively pursued alternative strategic possibilities for
the last three years and has been unsatisfied with the results. The Board
approved the proposed tender offer as a means of distributing up to $18 million
to stockholders who choose to participate in the proposed offer while retaining
enough cash to continue development of Zonagen's remaining technologies.

         Zonagen has 11,479,648 shares of common stock outstanding. The closing
price for Zonagen's common stock on The Nasdaq National Market on October 16,
2003, the last day of trading before the announcement of the tender offer, was
$1.68 per share.

         Neither Zonagen nor its Board of Directors make any recommendation as
to whether stockholders should tender their shares. Stockholders must make their
own decision as to whether to tender their shares and, if so, how many shares to
tender and at what price.

         ZONAGEN URGES ALL STOCKHOLDERS TO READ THE OFFER TO PURCHASE AND THE
RELATED DOCUMENTS FILED WITH SUCH OFFER TO PURCHASE WHEN IT IS AVAILABLE BECAUSE
IT WILL CONTAIN IMPORTANT INFORMATION. STOCKHOLDERS MAY OBTAIN A COPY OF THE
OFFER TO PURCHASE AND RELATED DOCUMENTS FOR FREE AT THE COMMISSION'S WEB SITE AT
WWW.SEC.GOV. ZONAGEN WILL ALSO PROVIDE AT NO CHARGE A COPY OF THE OFFER TO
PURCHASE AND ANY OTHER RELATED DOCUMENTS TO ANY STOCKHOLDER WHO REQUESTS SUCH
DOCUMENTS BY CONTACTING ZONAGEN AT (281) 719-3400.



         ABOUT ZONAGEN

         Zonagen is engaged in the development of pharmaceutical products that
address diseases and conditions associated with the human reproductive system.

         THIS PRESS RELEASE CONTAINS FORWARD-LOOKING STATEMENTS CONCERNING
ZONAGEN'S TENDER OFFER. FACTORS THAT MAY AFFECT FUTURE RESULTS INCLUDE THE
RESPONSE OF STOCKHOLDERS TO THE TENDER OFFER, FUTURE GENERAL AND SECTOR ECONOMIC
AND MARKET CONDITIONS, THE IMPACT OF GOVERNMENT REGULATION OF TENDER OFFERS AND
DECISIONS OF THE BOARD OF DIRECTORS. PLEASE REVIEW REPORTS FILED BY ZONAGEN,
INCLUDING THE FORTHCOMING OFFER TO PURCHASE WHICH WILL BE FILED WITH THE
SECURITIES AND EXCHANGE COMMISSION, FOR ADDITIONAL INFORMATION CONCERNING
FACTORS THAT COULD AFFECT ZONAGEN'S BUSINESS.