ECOLAB INC. — Director's Dealing 2011

May 13, 2011

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: ECOLAB INC (ECL)
CIK: 0000031462
Period of Report: 2011-05-11

Reporting Person: Mason Phillip J (President, EMEA Sector)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2011-05-11	Common Stock	M	50000	$29.29	Acquired	54008	Direct
2011-05-11	Common Stock	F	36284	$52.205	Disposed	17724	Direct
2011-05-11	Common Stock	M	10800	$34.50	Acquired	28524	Direct
2011-05-11	Common Stock	F	8700	$52.205	Disposed	19824	Direct
2011-05-11	Common Stock	M	45400	$34.075	Acquired	65224	Direct
2011-05-11	Common Stock	F	36365	$52.205	Disposed	28859	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2011-05-11	Employee Stock Option (Right to Buy)	$29.29	M	50000	Disposed	2014-05-07	Common Stock (50000)	Direct
2011-05-11	Employee Stock Option (Right to Buy)	$34.50	M	10800	Disposed	2014-12-09	Common Stock (10800)	Direct
2011-05-11	Employee Stock Option (Right to Buy)	$34.075	M	45400	Disposed	2015-12-07	Common Stock (45400)	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	588.661	Indirect

Footnotes

F1: Reflects the reporting person's payment of the exercise price and withholding taxes for a stock option issued in accordance with Rule 16b-3 by withholding shares of Ecolab Common Stock.

F2: Number of UNITS in the Ecolab Stock Fund of the Ecolab Savings Plan (401(k) Plan) as of March 31, 2011. Includes 2.056 UNITS acquired since the reporting person's last report. (The 588.661 UNITS are the equivalent of approximtely 1,097 SHARES of the issuer's Common Stock.)

F3: The option became exercisable, on a cumulative basis, as to one-third of the option shares (excluding any fractional portion less than one share) on each of the first and second anniversaries of the date of grant and as to the remaining shares on the third anniversary of the date of grant.