Exhibit 99.1

                                  CERTIFICATION
                                       OF
               CHIEF EXECUTIVE OFFICER AND CHIEF FINANCIAL OFFICER

         Pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906
of the Sarbanes-Oxley Act of 2002, each of the undersigned officers of Manhattan
Pharmaceuticals, Inc. do hereby certify that:

                  (a) the Quarterly Report on Form 10-QSB of Manhattan
Pharmaceuticals, Inc. for the quarter ended March 31, 2003 (the "Report:) fully
complies with the requirements of Section 13(a) or 15(d) of the Securities
Exchange Act of 1934; and

                  (b) information contained in the Report fairly presents, in
all material respects, the financial condition and results of operations of
Manhattan Pharmaceuticals, Inc.



Dated: May 15, 2003                        /s/ Leonard Firestone
                                           -------------------------------------
                                           Leonard Firestone
                                           President and Chief Executive Officer


Dated: May 15, 2003                        /s/ Nicholas J. Rossettos
                                           -------------------------------------
                                           Nicholas J. Rossettos
                                           Chief Financial Officer