EXHIBIT 32.1

                    CERTIFICATION OF CHIEF EXECUTIVE OFFICER
                         CALLISTO PHARMACEUTICALS, INC.
              FORM 10-QSB FOR THE QUARTER ENDED SEPTEMBER 30, 2003
                 PURSUANT TO 18 U.S.C. SECTION 1350, AS ADOPTED
            PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

         I am the Chief Executive Officer of Callisto Pharmaceuticals, Inc., a
Delaware corporation (the "Company"). I am delivering this certificate in
connection with the Form 10-QSB of the Company for the quarter ended September
30, 2003 and filed with the Securities and Exchange Commission ("Form 10-QSB").

         Pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906
of the Sarbanes-Oxley Act of 2002, I hereby certify that, to the best of my
knowledge, the Form 10-QSB fully complies with the requirements of Section 13(a)
or Section 15(d) of the Securities Exchange Act of 1934 and that the information
contained in the Form 10-QSB fairly presents, in all material respects, the
financial condition and results of operations of the Company.

Date: November 13, 2003

                                            /s/ Gary S. Jacob
                                            -----------------
                                            Gary S. Jacob
                                            Chief Executive Officer