Cupertino, Calif. – August 27, 2008 – ArcSight, Inc. (Nasdaq: ARST) today announced that it will issue a press release reporting financial results for the fiscal first quarter ended July 31, 2008 after the close of the market on September 9, 2008.

ArcSight will host a conference call and live webcast to discuss those financial results for investors and analysts at 2:00 p.m. Pacific Time on September 9, 2008. To access the conference call, dial 877-397-0250 for the U.S. or Canada and 719-325-4916 for international callers. The webcast will be available live on the Investor Relations section of the company’s website at www.arcsight.com. An audio replay of the call will also be available to investors by phone beginning at approximately 4:00 p.m. Pacific Time on September 9, 2008 until 11:59 p.m. Pacific Time on September 16, 2008, by dialing 888-203-1112 for the U.S. or Canada or 719-457-0820 for international callers, and entering passcode 7524287. In addition, an archived webcast will be available on the Investor Relations section of the company’s website at www.arcsight.com.

About ArcSight
ArcSight is a leading global provider of compliance and security management solutions that protect enterprises and government agencies. ArcSight helps customers comply with corporate and regulatory policy, safeguard their assets and processes and control risk. The ArcSight platform collects and correlates user activity and event data across the enterprise so that businesses can rapidly identify, prioritize and respond to compliance violations, policy breaches, cybersecurity attacks and insider threats. For more information, visit www.arcsight.com.

© 2008 ArcSight, Inc. All rights reserved. ArcSight and the ArcSight logo are trademarks of ArcSight, Inc

Contact Information:
Robert Dougherty
415-293-4427
IR@arcsight.com
robert.dougherty@fdashtonpartners.com