EXHIBIT 15

Board of Directors and Stockholders
Aon Corporation

We are aware of the incorporation by reference in the Registration Statements of
Aon Corporation ("Aon") described in the following table of our report dated
August 1, 1995 relating to the unaudited condensed consolidated interim
financial statements of Aon Corporation which are included in its Form 10-Q for
the quarter ended June 30, 1995:

Registration Statement
----------------------
  Form        Number                         Purpose
  ----        ------                         -------

   S-8       2-79114      Pertaining to Aon's stock option plan
   S-8       2-82791      Pertaining to Aon's stock option plan
   S-8       33-27984     Pertaining to Aon's savings plan
   S-8       33-42575     Pertaining to Aon's stock award plan and stock option 
                            plan

   S-8       33-59037     Pertaining to Aon's stock award plan and stock option 
                            plan
   S-3       33-57562     Registration of Aon's 8% cumulative perpetual 
                            preferred stock and 6 1/4% cumulative convertible 
                            exchangeable preferred stock 

Pursuant to Rule 436(c) of the Securities Act of 1933, our report is not a part 
of the registration statements prepared or certified by accountants within the 
meaning of Section 7 or 11 of the Securities Act of 1933.

                                            [Ernst & Young LLP]
                                           
                                        ERNST & YOUNG LLP
Chicago, Illinois
August 1, 1995

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