Ownership Submission
FORM 5
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
Form 3 Holdings Reported
Form 4 Transactions Reported
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

ANNUAL 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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1. Name and Address of Reporting Person *
SMITH MARK D
 2. Issuer Name and Ticker or Trading Symbol
SMITH A O CORP [AOS] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director _____ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
(Last)
(First)
(Middle)

3725 WEST GRACE AVENUE		 3. Statement for Issuer's Fiscal Year Ended (Month/Day/Year)
12/31/2010
(Street)


MEQUON, WI 53092		 4. If Amendment, Date Original Filed(Month/Day/Year)
 6. Individual or Joint/Group Reporting
(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 at end of Issuer's Fiscal Year
(Instr. 3 and 4)		 6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)		 7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Amount (A) or (D) Price
Common Stock             19,453 (1) D  
Common Stock 01/29/2010   G 582 A $ 0 5,556 I In trust (2)
Common Stock 07/07/2010   G 578 A $ 0 9,201 (3) I In trust (2)
Common Stock 12/17/2010   G 659 D $ 0 8,542 I In trust (2)
Common Stock 06/28/2010   G 579 A $ 0 1,920 (4) I Held by spouse

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number. SEC 2270 (9-02)

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 at End of Issuer's Fiscal Year
(Instr. 4)		 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)		 11. Nature of Indirect Beneficial Ownership
(Instr. 4)
(A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Class A Common Stock $ 0 (5)             (6)   (7) Common Stock
0
  43,149 (8)
I
In trust (2)
Class A Common Stock $ 0 (5)             (6)   (7) Common Stock
0
  919 (9)
I
Held by spouse

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
SMITH MARK D
3725 WEST GRACE AVENUE
MEQUON, WI 53092		   X      

Signatures

Kenneth J. Maciolek, Attorney-in-Fact for Mark D. Smith 02/04/2011
**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) On November 15, 2010, the common stock of A. O. Smith Corporation split 3-for-2, resulting in the reporting person's ownership of 6,484 additional shares of common stock.
(2) The reporting person beneficially owns the shares as settlor of a revocable family trust.
(3) On November 15, 2010, the common stock of A. O. Smith Corporation split 3-for-2, resulting in the reporting person's beneficial ownership of 3,067 additional shares of common stock.
(4) On November 15, 2010, the common stock of A. O. Smith Corporation split 3-for-2, resulting in the reporting person's beneficial ownership of 640 additional shares of common stock.
(5) 1 for 1
(6) Convertible at any time.
(7) None.
(8) On November 15, 2010, the common stock of A. O. Smith Corporation split 3-for-2, resulting in the reporting person's beneficial ownership of 14,383 additional shares of Class A Common Stock.
(9) On November 15, 2010, the common stock of A. O. Smith Corporation split 3-for-2, resulting in the reporting person's beneficial ownership of 306 additional shares of Class A Common Stock.

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