EXHIBIT 23 CONSENT OF INDEPENDENT AUDITORS Marsh & McLennan Companies, Inc.: We consent to the incorporation by reference in the previously filed Form S-8 Registration Statements (Registration File Nos. 2-58660, 2-65096, 2-82938, 33-32880, 33-48803, 33-48804, 33-48807 and 33-54349) and in the previously filed Form S-4 Registration Statement (Registration File No. 33-24124) of our reports appearing in, and incorporated by reference in, this Annual Report on Form 10-K of Marsh & McLennan Companies, Inc. for the year ended December 31, 1994. /s/ Deloitte & Touche LLP DELOITTE & TOUCHE LLP New York, New York March 28, 1995