X0303 4 2010-07-15 false 0001373671 Isilon Systems, Inc. ISLN 0001378830 Patel Sujal M C/O ISILON SYSTEMS, INC. 3101 WESTERN AVENUE SEATTLE WA 98121 true true false false President & CEO Common Stock 2010-07-15 4 S false 12000 14.2691 D 2439164 D Common Stock 2010-07-16 4 S false 12000 13.8351 D 2427164 D The sales reported by Mr. Patel were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 31, 2009. The "Amount" and "Price" reported in this Column 4 reflect the aggregate number and weighted-average price, respectively, of shares disposed. These shares were sold in multiple transactions at prices ranging from $14.08 to $14.69, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the SEC staff, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (2) and (4) to this Form 4. The sales reported by Mr. Patel were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 31, 2009. The "Amount" and "Price" reported in this Column 4 reflect the aggregate number and weighted-average price, respectively, of shares disposed. These shares were sold in multiple transactions at prices ranging from $13.62 to $14.32, inclusive. Keenan M. Conder, Attorney-in-Fact 2010-07-19