SECURITIES AND EXCHANGE COMMISSION
                                          Washington, D.C. 20549

                                           --------------------

                                                 FORM 8-K

                                              CURRENT REPORT

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


<TABLE>
<CAPTION>
<S>                                                 <C> <C>
                                               May 18, 2004
---------------------------------------------------------------------------------------------------------
                                    (Date of earliest event reported)



                                     Marsh & McLennan Companies, Inc.
                 ------------------------------------------------------------------------
                          (Exact name of registrant as specified in its charter)




              Delaware                            1-5998                           36-2668272
---------------------------------------------------------------------------------------------------------
  (State or other jurisdiction           (Commission File Number)                (IRS Employer
        of incorporation)                                                      Identification No.)



1166 Avenue of the Americas, New York, NY                                            10036
---------------------------------------------------------------------------------------------------------
(Address of principal executive offices)                                           (Zip Code)



                                               (212) 345-5000
   ---------------------------------------------------------------------------------------------------
                            (Registrant's telephone number, including area code)




</TABLE>

<PAGE>





ITEM 5.  Other Events.

         On May 18, 2004, Marsh & McLennan Companies, Inc. issued a press
release, a copy of which is attached as Exhibit 99.1 hereto and is incorporated
herein by reference.


ITEM 7.  Financial Statements and Exhibits.

         (c)  Exhibits


Exhibit Reference Number            Exhibit Description

99.1                                Press release, dated May 18, 2004, issued by
                                    Marsh & McLennan Companies, Inc.




<PAGE>





                                   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.

                                               MARSH & McLENNAN COMPANIES, INC.



                                               By:  /s/ Leon J. Lichter
                                                    ----------------------------
                                                    Name:   Leon J. Lichter
                                                    Title:  Vice President &
                                                             Corporate Secretary



Date:  May 18, 2004
       ------------



<PAGE>





Exhibit Index

99.1   Press release, dated May 18, 2004, issued by
       Marsh & McLennan Companies, Inc.
[{"type": "8-K", "sequence": "1", "filename": "f8kmay18-04.txt", "description": "MAY 18, 2004", "secsgml_size_bytes": 3324}]
{"company-data": {"conformed-name": "MARSH & MCLENNAN COMPANIES INC", "cik": "0000062709", "assigned-sic": "6411", "irs-number": "362668272", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "8-K", "act": "34", "file-number": "001-05998", "film-number": "04817526"}, "business-address": {"street1": "1166 AVENUE OF THE AMERICAS", "city": "NEW YORK", "state": "NY", "zip": "10036", "phone": "2123455000"}, "mail-address": {"street1": "1166 AVENUE OF THE AMERICAS", "city": "NEW YORK", "state": "NY", "zip": "10036"}, "former-company": {"former-conformed-name": "MARLENNAN CORP", "date-changed": "19760505"}}
SECURITIES AND EXCHANGE COMMISSION
                                          Washington, D.C. 20549

                                           --------------------

                                                 FORM 8-K

                                              CURRENT REPORT

                                 PURSUANT TO SECTION 13 OR 15(d) OF THE
                                     SECURITIES EXCHANGE ACT OF 1934
May 18, 2004
---------------------------------------------------------------------------------------------------------
                                    (Date of earliest event reported)

                                     Marsh & McLennan Companies, Inc.
                 ------------------------------------------------------------------------
                          (Exact name of registrant as specified in its charter)

              Delaware                            1-5998                           36-2668272
---------------------------------------------------------------------------------------------------------
  (State or other jurisdiction           (Commission File Number)                (IRS Employer
        of incorporation)                                                      Identification No.)

1166 Avenue of the Americas, New York, NY                                            10036
---------------------------------------------------------------------------------------------------------
(Address of principal executive offices)                                           (Zip Code)

                                               (212) 345-5000
   ---------------------------------------------------------------------------------------------------
                            (Registrant's telephone number, including area code)
ITEM 5.  Other Events.

         On May 18, 2004, Marsh & McLennan Companies, Inc. issued a press
release, a copy of which is attached as Exhibit 99.1 hereto and is incorporated
herein by reference.

ITEM 7.  Financial Statements and Exhibits.

         (c)  Exhibits

Exhibit Reference Number            Exhibit Description

99.1                                Press release, dated May 18, 2004, issued by
                                    Marsh & McLennan Companies, Inc.
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.

                                               MARSH & McLENNAN COMPANIES, INC.

                                               By:  /s/ Leon J. Lichter
                                                    ----------------------------
                                                    Name:   Leon J. Lichter
                                                    Title:  Vice President &
                                                             Corporate Secretary

Date:  May 18, 2004
       ------------
Exhibit Index

99.1   Press release, dated May 18, 2004, issued by
       Marsh & McLennan Companies, Inc.