EXHIBIT 24

POWER OF ATTORNEY

I, D.P.M. Verbeek ('Grantor'), hereby confirm, constitute and
appoint each of Jennifer L. Kraft and Richard E. Barry, severally
and not jointly, signing singly, as the true and lawful attorney-
in-fact of Grantor to:
1. execute for and on behalf of Grantor, in Grantor's capacity as
an officer, for purposes of Section 16 of the Securities Exchange
Act of 1934, as amended (the 'Exchange Act'), of Aon Corporation
(the 'Company'), Forms 3, 4 and 5, including but not limited to
any amendments thereto, in accordance with Section 16(a) of the
Exchange Act, and the rules promulgated thereunder, which may be
necessary or desirable as a result of Grantor's ownership of or
transaction in securities of Aon Corporation; and
2. do and perform any and all acts for and on behalf of Grantor
which may be necessary or desirable to complete and execute any
such Form 3, 4 or 5 or any amendments thereto, and timely file
such form with the United States Securities and Exchange
Commission (the 'SEC') and any other entity or person.

Grantor hereby grants to each such attorney-in-fact full power
and authority to do and perform any and every act and thing
whatsoever requisite, necessary or proper to be done in the
exercise of any of the rights and powers herein granted, as fully
to all intents and purposes as the undersigned might or could do
if personally present, with full power of substitution or
revocation, hereby ratifying and confirming all that such
attorney-in-fact, or such attorney-in-fact's substitute or
substitutes, shall lawfully do or cause to be done by virtue of
this power of attorney and the rights and powers herein granted.
Grantor acknowledges that the foregoing attorneys-in-fact, in
serving in such capacity at the request of Grantor, are not
assuming, nor is the Company assuming, any of Grantor's
responsibilities to comply with Section 16 of the Exchange Act.

This Power of Attorney shall be effective on the date set forth
below and shall continue in full force and effect until the date
on which Grantor shall cease to be subject to Section 16 of the
Exchange Act and the rules promulgated thereunder or until such
earlier date on which written notification executed by Grantor is
filed with the SEC expressly revoking this Power of Attorney.

Grantor hereby revokes all prior powers of attorney that are in
effect and filed with the SEC.

IN WITNESS WHEREOF, Grantor has caused this Power of Attorney to
be executed as of this 1st day of December, 2003.

Signature:   /s/ D.P.M. Verbeek
		D.P.M. Verbeek