SEC Form 3

FORM 3

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

OMB APPROVAL OMB Number: 3235-0104 Estimated average burden hours per response: 0.5

1. Name and Address of Reporting Person* Pettigrew Thomas P (Last) (First) (Middle) C/O ISILON SYSTEMS, INC. 3101 WESTERN AVENUE (Street) SEATTLE WA 98121 (City) (State) (Zip)	2. Date of Event Requiring Statement (Month/Day/Year) 12/14/2006	3. Issuer Name and Ticker or Trading Symbol Isilon Systems, Inc. [ ISLN ]
		4. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director 10% Owner X Officer (give title below) Other (specify below) VP Global Sales Partners	5. If Amendment, Date of 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

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	62,932	D
Common Stock	202,500(1)	D
Common Stock	33,333(2)	D

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Employee Stock Option (Right to Buy)	(3)	04/29/2014	Common Stock	47,743	$0.22	D
Employee Stock Option (Right to Buy)	(4)	03/10/2015	Common Stock	14,322	$0.22	D
Employee Stock Option (Right to Buy)	(5)	03/30/2016	Common Stock	66,666	$0.82	D

Explanation of Responses:

1. The shares of common stock are subject to a right of repurchase in favor of the Issuer upon Mr. Pettigrew's cessation of service, which right of repurchase terminates on February 2, 2008.

2. The shares of common stock are subject to a right of repurchase in favor of the Issuer upon Mr. Pettigrew's cessation of service, which right of repurchase terminates on January 1, 2010.

3. On April 29, 2004, Mr. Pettigrew was granted an option to purchase 104,165 shares of Common Stock, of which 56,422 shares have been exercised. The option is exercisable at the rate of 1/4th of the shares on April 29, 2005 and 1/36th of the remaining shares on each monthly anniversary thereafter.

4. On March 10, 2005, Mr. Pettigrew was granted an option to purchase 20,832 shares of Common Stock, of which 6,510 shares have been exercised. The option is exercisable at the rate of 1/4th of the shares on March 10, 2006 and 1/36th of the remaining shares on each monthly anniversary thereafter.

5. The option is exercisable at the rate of 1/4th of the shares on March 10, 2007 and 1/36th of the remaining shares on each monthly anniversary thereafter.

Remarks:

	/s/ Douglas Choi, attorney-in-fact	12/13/2006
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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 Number.