16.05.2005 – 20:23

Aon Corporation

Aon to Webcast Annual Stockholders' Meeting

Chicago (ots/PRNewswire)

Aon Corporation (NYSE: AOC) Executive
Chairman, Patrick G. Ryan, will host the Company's Annual
Stockholders' Meeting on Friday, May 20, 2005 at 10:00 a.m. (CDT). A
webcast of the presentation and questions by stockholders attending
the meeting in Chicago will be available via the Internet. This
listen-only webcast can be accessed by going to the home page of
Aon's web site at http://www.aon.com . The webcast will be archived
for two weeks.

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 47,000 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.

This press release may contain certain statements related to
future results, or states our intentions, beliefs and expectations or
predictions for the future which are forward-looking statements as
that term is defined in the Private Securities Litigation Reform Act
of 1995. These forward-looking statements are subject to certain
risks and uncertainties that could cause actual results to differ
materially from either historical or anticipated results depending on
a variety of factors. Potential factors that could impact results
include: general economic conditions in different countries in which
we do business around the world, changes in global equity and fixed
income markets that could affect the return on invested assets,
fluctuations in exchange and interest rates that could influence
revenue and expense, rating agency actions that could affect our
ability to borrow funds, funding of our various pension plans,
changes in the competitive environment, changes in commercial
property and casualty markets and commercial premium rates that could
impact revenues, changes in revenues and earnings due to the
elimination of contingent commissions, other uncertainties
surrounding a new compensation model, the impact of regulatory
investigations brought by state attorneys general and state insurance
regulators related to our compensation arrangements with underwriters
and related issues, the impact of class actions and individual
lawsuits including client class actions, securities class actions,
derivative actions, and ERISA class actions, the cost of resolution
of other contingent liabilities and loss contingencies, and the
difference in ultimate paid claims in our underwriting companies from
actuarial estimates.

Further information concerning the Company and its business,
including factors that potentially could materially affect the
Company's financial results, is contained in the Company's filings
with the Securities and Exchange Commission.

    Investor Contact:  Craig Streem
                       Corporate Vice President, Investor Relations
                       +1-312-381-3983
    Media Contact:     Gary Sullivan
                       Senior Vice President, Corporate Communications
                       +1-312-381-2467

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

Contact:

Investors, Craig Streem, Corporate Vice President, Investor
Relations, +1-312-381-3983; or, Media, Gary Sullivan, Senior Vice
President, Corporate Communications, +1-312-381-2467