SMITH A O CORP — Director's Dealing 2005

May 16, 2005

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: SMITH A O CORP (AOS)
CIK: 0000091142
Period of Report: 2005-05-13

Reporting Person: MASSA RONALD E (Senior Vice President)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2005-05-13	Common Stock	M	10300	$16.667	Acquired	34906	Direct
2005-05-13	Common Stock	S	7300	$29.097	Disposed	27606	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2005-05-13	Employee Stock Options (Right to Buy)	$16.667	M	10300	Disposed	2005-10-10	Common Stock (10300)	Direct

Footnotes

F1: Options were granted under the A. O. Smith Corporation 1990 Long-Term Executive Incentive Compensation Plan, a Rule 16b-3 Plan.