FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person * OHALLERAN MICHAEL D   2. Issuer Name and Ticker or Trading Symbol AON CORP [AOC] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Senior Exec VP (Last) (First) (Middle) AON CORPORATION - CORPORATE LAW DEPT, 200 EAST RANDOLPH STREET, 8TH FLOOR 3. Date of Earliest Transaction (Month/Day/Year) 01/02/2006 (Street) CHICAGO, IL 60601 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock               15,642 D   Common Stock 12/01/2005   G V 100 D (1) 63,136 I Trust for Self Common Stock 12/30/2005   G(2) V 610 D (1) 62,526 I Trust for Self Common Stock 01/02/2006   M(3)   13,500 A $ 35.97 76,026 I Trust for Self Common Stock 01/02/2006   F(4)   4,139 D $ 35.97 71,887 I Trust for Self Common Stock 01/02/2006   M(3)   6,750 A $ 35.97 78,637 I Trust for Self Common Stock 01/02/2006   F(4)   1,988 D $ 35.97 76,649 I Trust for Self Common Stock 01/02/2006   M(3)   4,500 A $ 35.97 81,149 I Trust for Self Common Stock 01/02/2006   F(4)   1,326 D $ 35.97 79,823 I Trust for Self Common Stock 01/02/2006   M(3)   2,250 A $ 35.97 82,073 I Trust for Self Common Stock 01/02/2006   F(4)   663 D $ 35.97 81,410 I Trust for Self Common Stock 01/02/2006   M(3)   2,250 A $ 35.97 83,660 I Trust for Self Common Stock 01/02/2006   F(4)   887 D $ 35.97 82,773 I Trust for Self Common Stock 01/02/2006   M(3)   2,250 A $ 35.97 85,023 I Trust for Self Common Stock 01/02/2006   F(4)   887 D $ 35.97 84,136 I Trust for Self Common Stock 12/01/2005   G V 550 D (5) 37,749 (6) I Trust for Spouse Common Stock 12/27/2005   G(2) V 610 D (5) 37,139 (6) I Trust for Spouse Common Stock 12/27/2005   G(2) V 305 A (5) 1,353 (6) I By Daughter Common Stock 12/30/2005   G(2) V 305 A (1) 1,658 (6) I By Daughter Common Stock 12/27/2005   G(2) V 305 A (5) 1,353 (6) I By Son Common Stock 12/30/2005   G(2) V 305 A (1) 1,658 (6) I By Son Common Stock               26,618 I Through Aon Savings Plan and ESOP

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Stock Award (Right to Receive)

(7)

01/02/2006

A

22,500

01/02/2009(8)

01/02/2016

Common Stock

22,500

$ 0

22,500

D

Common Stock

(7)

01/02/2006

M

13,500

01/02/2006

01/02/2006

Common Stock

13,500

$ 0

0

D

Common Stock

(7)

01/02/2006

M

6,750

01/02/2006

01/02/2006

Common Stock

6,750

$ 0

20,250

D

Common Stock

(7)

01/02/2006

M

4,500

01/02/2006

01/02/2006

Common Stock

4,500

$ 0

18,000

D

Common Stock

(7)

01/02/2006

M

2,250

01/02/2006

01/02/2006

Common Stock

2,250

$ 0

9,000

D

Common Stock

(7)

01/02/2006

M

2,250

01/02/2006

01/02/2006

Common Stock

2,250

$ 0

13,500

D

Common Stock

(7)

01/02/2006

M

2,250

01/02/2006

01/02/2006

Common Stock

2,250

$ 0

15,750

D

Phantom Stock (Deferred Stock Awards)

(9)

(10)

(10)

Common Stock

(11)

166,377

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
OHALLERAN MICHAEL D AON CORPORATION - CORPORATE LAW DEPT 200 EAST RANDOLPH STREET, 8TH FLOOR CHICAGO, IL 60601			Senior Exec VP

Signatures

/s/ Jennifer L. Kraft - by Jennifer L. Kraft pursuant to a power of attorney from Michael D. O'Halleran		01/04/2006
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	The reporting person made a gift of the shares on the transaction date indicated in Column 2.
(2)	Gift of 305 shares to each of the reporting person's daughter and son who share the reporting person's household. The reporting person disclaims beneficial ownership of the shares held by his daughter and son, and this report should not be deemed an admission that the reporting person is the beneficial owner of the shares held by his daughter or son for purposes of Section 16 or for any other purpose.
(3)	Shares of common stock acquired upon the vesting of a restricted stock award.
(4)	Shares of common stock withheld by the issuer for the payment of withholding taxes in connection with the vesting of a restricted stock award.
(5)	The reporting person's spouse made a gift of the shares on the transaction date indicated in Column 2.
(6)	The reporting person disclaims beneficial ownership of these shares.
(7)	The restricted stock award converts to shares of common stock on a 1-for-1 basis.
(8)	Awards will vest in accordance with the Aon Stock Incentive Plan as follows: 20% of the awards will vest on each of the third and tenth anniversaries of the date of grant, and 10% of the awards will vest on each of the fourth through ninth anniversaries of the date of grant.
(9)	The phantom shares convert to shares of common stock on a 1-for-1 basis.
(10)	The phantom stock represents vested award shares of which the reporting person has deferred receipt.
(11)	Represents the phantom share balance as of December 31, 2005.

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