EXHIBIT 32




          Certification of Chief Executive and Chief Financial Officers


     The certification set forth below is being submitted in connection with the
Quarterly Report on Form 10-Q for the fiscal quarter ended March 31, 2004 (the
"Report") for the purpose of complying with Rule 13a-14(b) or Rule 15d-14(b) of
the Securities Exchange Act of 1934, as amended (the "Exchange Act") and Section
1350 of Chapter 63 of Title 18 of the United States Code.

     Jeffrey W. Greenberg, the Chief Executive Officer and Sandra S. Wijnberg,
the Chief Financial Officer of Marsh & McLennan Companies, Inc. each certifies
that, to the best of his or her knowledge:

     1.  the Report fully complies with the requirements of Section 13(a) of the
         Securities Exchange Act of 1934; and

     2.  the information contained in the Report fairly presents, in all
         material respects, the financial condition and results of operations
         of Marsh & McLennan Companies, Inc.


Dated: May 10, 2004
                                                     Name:  Jeffrey W. Greenberg
                                                     ---------------------------
                                                     Chief Executive Officer



Dated: May 10, 2004
                                                     Name:  Sandra S. Wijnberg
                                                     ---------------------------
                                                     Chief Financial Officer