Key Corp, Peppers & Rogers, Virgin Mobile USA to Headline Siebel CustomerWorld 2005; Focus Is on Helping Companies Better Serve Their Customers at New Industry Conference

Keynote presenters Kevin Riley, Executive Vice President, CustomerInformation and Relationship Management of Key Corp and Michael Parks,CIO of Virgin Mobile USA will share their experiences on how theircompanies have maximized the value of their customer relationships.Don Peppers, Founding Partner, Peppers & Rogers Group, will share hisperspectives based on more than a decade of experience providingcustomer-focused relationship management strategies for businesses. Inaddition, Siebel Systems executives George T. Shaheen, Chief ExecutiveOfficer, and Bruce Cleveland, Senior Vice President, Products, willdiscuss the company's future plans and product strategy, including thecompany's next-generation service-oriented architecture (SOA)solution.

"Many leading organizations have agreed to share theirexperiences, illustrating the importance today's companies place onbuilding customer-focused organizations," said Patty Azzarello, SeniorVice President and Chief Marketing Officer, Siebel Systems."Regardless of size or industry, companies today recognize thatfocusing on their customers is the path to growth and competitiveadvantage. That's why we redesigned our annual user conference tocreate a new program focused on helping companies find solutions totheir most pressing business challenges, receive the information andadvice they need to get more out of their Siebel solutions, and walkaway with real insight they can apply to their businesses to buildstronger customer relationships that lead to real results."

The annual conference, which is expected to attract Siebelcustomers, solution providers, speakers, and presenters in the CRM andbusiness analytics communities, will feature more than 200 customertestimonials, roundtable discussions, and presentations by subjectmatter experts. The conference is designed for both IT and businessdecision-makers and will offer separate tracks for these audiences toprovide the insight, strategies, and best practices needed to buildcustomer-focused organizations. The conference's Platinum sponsors areDeloitte Consulting LLP, HP and IBM.

Siebel Business Intelligence (BI) Summit Running Concurrently

Siebel BI Summit will gather thought leaders and participants inthe BI industry and focus on key trends and next-generationrequirements for enterprise-wide business intelligence, datawarehousing, performance management, customer insight, and analyticapplications. The conference runs concurrently with SiebelCustomerWorld. More information about Siebel CustomerWorld 2005 andSiebel BI Summit 2005, including registration details, is available atwww.siebelcustomerworld.com or www.siebelbisummit.com.

About Siebel Systems

Siebel Systems is a leading provider of customer-facing solutionsthat deliver demonstrable business results and long-term competitiveadvantage. Siebel's multichannel offerings allow organizations tointelligently manage and coordinate all customer interactions acrossthe Web, contact center, field sales/service force, branch/retailnetwork, and indirect and partner distribution channels. Siebelsolutions draw upon the company's best-in-class capabilities incustomer relationship management (CRM), business intelligence, andcustomer data integration and can be deployed as licensed software oras a hosted service. Siebel solutions are tailored to the unique needsof 23 industries and incorporate industry-specific business processes,best practices, and business insight. They are the product of morethan $2 billion in R&D investments and reflect over 11 years ofexperience with more than 4,000 organizations. Together with itsextensive global network of alliance partners, Siebel provides thepeople, process, and technology expertise critical in driving businessvalue from the deployment of customer-facing solutions. Over 3 millionusers worldwide in organizations of all sizes depend on Siebelsolutions to deliver dramatic improvements in how they identify,acquire, retain, and serve customers. For more information, visitwww.siebel.com.

For more information on Siebel Systems solutions and services,please visit our Web site: CRM - http://www.siebel.com/crm; OnDemandSolutions - http://www.crmondemand.com; Industry CRM -http://www.siebel.com/industry-crm; Call Center and Service -http://www.siebel.com/call-center; Sales Force Automation -http://www.siebel.com/sales-force-automation; Marketing Automation -http://www.siebel.com/marketing-automation; Business Intelligence -http://www.siebel.com/business-intelligence; Integration Solutions -http://www.siebel.com/integration-solutions; CRM Services -http://www.siebel.com/crm-services

Except for the historical information contained herein, this pressrelease contains forward-looking statements that involve risk oruncertainties. Future operating results of Siebel Systems may differfrom the results discussed or forecasted in the forward-lookingstatements due to factors that include, but are not limited to, risksassociated with customer relations, such as the availability of SiebelSystems' products and services, customer implementation of productsand services, relationships with customers, third-party vendors andsystems integrators, concentration of revenues in a relatively smallnumber of customers, existence of errors or defects in products,ability to successfully manage growth, significant current andexpected additional competition and the need to continue to expandproduct distribution and services offerings. Further information onpotential factors that could affect the financial results of SiebelSystems are included in Siebel Systems' Annual Report on Form 10-K,Quarterly Reports on Form 10-Q and its other filings with theSecurities and Exchange Commission, which are available atwww.sec.gov. Siebel Systems assumes no obligation to update theinformation in this press release.

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