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

                                    FORM 8-K

             CURRENT REPORT FILED PURSUANT TO SECTION 13 OR 15(d) OF
                       THE SECURITIES EXCHANGE ACT OF 1934

                                 DATE OF REPORT
                 (DATE OF EARLIEST EVENT REPORTED): JULY 1, 2004

                                  ZONAGEN, INC.
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)


                                                                                   
           DELAWARE                                      0-21198                                    76-0233274
(STATE OR OTHER JURISDICTION OF                   (COMMISSION FILE NUMBER)               (I.R.S. EMPLOYER IDENTIFICATION NO.)
 INCORPORATION OR ORGANIZATION)


                        2408 TIMBERLOCH PLACE, SUITE B-1
                           THE WOODLANDS, TEXAS 77380
              (ADDRESS OF PRINCIPAL EXECUTIVE OFFICES AND ZIP CODE)

                                 (281) 719-3400
              (REGISTRANT'S TELEPHONE NUMBER, INCLUDING AREA CODE)

ITEM 5. OTHER INFORMATION

      On July 1, 2004, Zonagen, Inc. (the "Company") announced in a press
release that it released results from its placebo-controlled challenge study of
Androxal(TM) in hypogonadal men.

      A copy of the Company's press release is attached hereto as Exhibit 99.1.
The press release is incorporated by reference herein and the foregoing
description of the press release is qualified in its entirety by reference to
the attached exhibit.

ITEM 7. FINANCIAL STATEMENTS AND EXHIBITS

      c. Exhibits

         Exhibit
         Number        Description
         ------        -----------
          99.1         Press Release dated July 1, 2004.


                                   SIGNATURES

      Pursuant to the requirements of the Securities Exchange Act of 1934, the
Registrant has duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.

                                    ZONAGEN, INC.
Date: July 2, 2004.

                                    By: /s/ Louis Ploth, Jr.
                                        ----------------------------------------
                                        Louis Ploth, Jr.
                                        Vice President, Business Development and
                                        Chief Financial Officer

                                  EXHIBIT INDEX



          Exhibit
          Number           Description
          -------          ------------
           99.1            Press Release dated July 1, 2004.