SAN MATEO, Calif., Nov. 10, 2004 -- Siebel Systems, Inc. (NASDAQ:SEBL), a leading provider of business applications software, today announced that T-Systems will deploy Siebel CRM OnDemand for approximately 1,000 sales professionals around the world to maximize sales performance. This hosted CRM implementation will be integrated with T-Systems' highly successful Siebel on premise deployment in Germany, where 2,800 staff are already using Siebel Sales to maximize sales performance. T-Systems' sales teams will use the combined hosted and on premise solution to close cross-border opportunities more quickly and achieve a higher standard of customer satisfaction.

"The combination of Siebel Systems' on premise CRM solution and Siebel CRM OnDemand will enable T-Systems to use a common sales model worldwide," said Peter Schmidt, Executive Vice President, T-Systems. "Having carefully evaluated our business needs, we concluded that Siebel CRM OnDemand would deliver fast, effective results with minimal up-front investment. Next year, we will integrate Siebel CRM OnDemand with our domestic Siebel on premise solution to enable seamless, global sales collaboration."

T-Systems, one of the leading information and communication (ICT) service providers in Europe, is a division of Deutsche Telekom AG. The company markets its world-class portfolio of integration, desktop, data center, and telecommunications solutions to Deutsche Telekom's largest business customers worldwide. More than 2,800 T-Systems sales, marketing, and service professionals in Germany currently rely on Siebel Systems' on premise CRM solution to manage relationships with large business customers.

Until now, the company's 20 international subsidiaries relied on a combination of paper-based and electronic systems to manage customer relationships. This undermined the company's ability to effectively sell in these territories and gain a universal view of its sales activities. Because the market for T-Systems' solutions is smaller and more dynamic in these territories than in Germany, T-Systems needed a fast, easy, and cost-effective CRM solution that could support its full range of sales, marketing, and service activities.

The company concluded that Siebel CRM OnDemand fit its business objectives because it does not require significant up-front investment, can be rapidly deployed, provides full pipeline visibility, and offers real-time and historical analytics. Most importantly, it would also integrate seamlessly with the company's domestic Siebel on premise solution -- so that T-Systems could implement a global team selling strategy among more than 3,800 staff worldwide and across multiple tiers of distribution.

"Siebel Systems continues to transform its business to deliver business results to our customers," said Bruce Cleveland, Senior Vice President and General Manager, OnDemand and SMB, Siebel Systems. "As the only CRM application software company to offer customers the ability to implement an on premise solution, a hosted solution, or a combination of the two, we have taken our customers' demand for business results into a reality. Our experience in the CRM market, coupled with unmatched deployment flexibility and product strength, provides global customers like T-Systems with an unrivaled sense of security in their CRM deployments."

Siebel CRM OnDemand, hosted in Germany, will be used by T-Systems in up to 20 countries across Europe, the Americas, and the Pacific Rim to access information on key sales opportunities, track pending opportunity milestones, and analyze pipeline and key accounts in real time. Sales teams will use Siebel Systems' hosted solution to schedule activities and appointments, compare average sales cycles, identify top-performing accounts, and establish new business opportunities within existing accounts.

Today's announcement builds on the relationship between Siebel Systems and T-Systems. Last month, the two companies announced an agreement under which T-Systems will sell, market, and deliver hosted CRM to businesses in Germany, Austria, Switzerland, the Czech Republic, Hungary, Poland, Slovakia, Croatia, and Russia starting in February 2005. In addition, T-Systems has provided sales, deployment, and integration services for Siebel Systems' on premise CRM solutions to tens of thousands of users in the telecommunications and finance industries since the two companies formed an alliance more than three years ago. T-Systems will offer its customers the ability to integrate Siebel on premise with its hosted CRM solution.

v T-Systems is the latest in a growing number of organizations to deploy Siebel CRM OnDemand. Following its European launch in April 2004, Siebel CRM OnDemand is experiencing significant success in the U.K., Italy, Germany, Switzerland, France, The Netherlands, Scandinavia, Russia, and The Czech Republic. European companies are now taking advantage of Siebel Systems' proven CRM capabilities in a hosted solution that enables companies to sell to, market to, and serve customers in English, French, German, Italian, and Spanish. Siebel CRM OnDemand is the industry's first and only hosted CRM solution designed to work in conjunction with on premise Siebel CRM solutions.

About Siebel CRM OnDemand

Siebel CRM OnDemand is a hosted CRM offering delivered over the Web and accessible from an Internet browser at a fixed price per user per month. Customers can deploy Siebel CRM OnDemand quickly, easily, and affordably without any up-front IT investments. Siebel CRM OnDemand delivers complete sales, marketing, and service functionality; built-in customer analytics; virtual call center technology; embedded best practices; and world-class hosting services and support. Siebel CRM OnDemand is now available for purchase. For more information, visit www.siebel.com or www.crmondemand.com.

About Siebel Systems

Siebel Systems, Inc. is a leading provider of business applications software, enabling corporations to sell to, market to, and serve customers across multiple channels and lines of business. With more than 4,000 customer deployments worldwide, Siebel Systems provides organizations with a proven set of industry-specific best practices, CRM applications, market-leading analytics products, and business processes, empowering them to consistently deliver superior customer experiences and establish more profitable customer relationships. Siebel Systems' sales and service facilities are located in more than 30 countries.

Except for the historical information contained herein, this press release contains forward-looking statements that involve risk or uncertainties. Future operating results of Siebel Systems may differ from the results discussed or forecasted in the forward-looking statements due to factors that include, but are not limited to, risks associated with customer relations, such as the availability of Siebel Systems' products and services, customer implementation of products and services, relationships with customers, third-party vendors and systems integrators, concentration of revenues in a relatively small number of customers, existence of errors or defects in products, ability to successfully manage growth, significant current and expected additional competition and the need to continue to expand product distribution and services offerings. Further information on potential factors that could affect the financial results of Siebel Systems are included in Siebel Systems' Annual Report on Form 10-K, Quarterly Reports on Form 10-Q and its other filings with the Securities and Exchange Commission, which are available at www.sec.gov. Siebel Systems assumes no obligation to update the information in this press release.

Siebel is a trademark of Siebel Systems, Inc. and may be registered in certain jurisdictions. All other product and company names mentioned are the property of their respective owners and are mentioned for identification purposes only.

Siebel Systems, Inc.
Stacey Burbach, 480-377-3725 
email: stacey.burbach@siebel.com