15.04.2005 – 18:36

Aon Corporation

Aon Dividend Announcement

Chicago (ots/PRNewswire)

Aon Corporation (NYSE: AOC) today
declared a quarterly cash dividend of US$0.15 per common share. The
cash dividend is payable on May 16, 2005 to common stockholders of
record at the close of business on May 3, 2005.

Aon Corporation ( http://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 48,000 professionals
in its 500 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.

Investor Contact:   Craig Streem
                         Corporate Vice President, Investor Relations
                         +1-312-381-3983
     Media Contact:      Dave Van de Walle
                         Aon Corporation, Public Relations
                         +1-312-381-5028
                          dave_vandewalle@aon.com

Web site: http://www.aon.com

Contact:

Investors, Craig Streem, Corporate Vice President, Investor
Relations, +1-312-381-3983, or Media, Dave Van de Walle Public
Relations, +1-312-381-5028, dave_vandewalle@aon.com , both of Aon
Corporation