( BW)(IL-AON)(AOC) Aon Dividend Announcement

    Business Editors

    CHICAGO--(BUSINESS WIRE)--April 16, 2004--Aon Corporation
(NYSE:AOC) today declared a quarterly cash dividend of $0.15 per
common share. The cash dividend is payable on May 17, 2004 to common
stockholders of record at the close of business on May 4, 2004.
    Aon Corporation (www.aon.com) is a leading provider of risk
management services, insurance and reinsurance brokerage, human
capital and management consulting, and specialty insurance
underwriting. The company employs approximately 54,000 professionals
in its 600 offices in more than 120 countries. Backed by broad
resources, industry knowledge and technical expertise, Aon
professionals help a wide range of clients develop effective risk
management and workforce productivity solutions.

    --30--YM/cg*

    CONTACT: Aon Corporation, Chicago
             Sean O'Neill, 312-381-3983 (Investor Contact)
             Al Orendorff, 312-381-3153 (Media Contact)