Siebel Systems, Inc. to Provide eBusiness Applications to Aventis Pharma; Global Pharmaceutical Leader to Implement Siebel ePharma 7.

Business Editors/High-Tech Writers

SAN MATEO, Calif.--(BUSINESS WIRE)--Jan. 29, 2002

Siebel Systems, Inc. (Nasdaq:SEBL), the world's leading provider of eBusiness applications software, today announced that it has reached an agreement with Aventis Pharma, a leading pharmaceutical company, to provide Siebel eBusiness Applications for use throughout Aventis Pharma's worldwide pharmaceutical business. Aventis Pharma is currently using Siebel ePharma -- a comprehensive suite of multichannel eBusiness software specifically designed to meet the unique needs of the pharmaceutical industry -- in six locations worldwide. The new agreement will permit Aventis Pharma to standardize on Siebel ePharma 7 for all remaining regions, including the U.S., EMEA, and Asia Pacific.

The agreement allows Aventis Pharma to design and develop a Global Competency Center, standardizing on Siebel ePharma 7, that will consolidate existing legacy systems and align the business processes of Aventis Pharma's call center, Electronic Territory Management System (ETMS) and data warehouse. Siebel eBusiness Applications will be integrated with Aventis Pharma's Documentum content management platform and SAP ERP systems. Siebel ePharma 7 will also facilitate consistent methodology and standards for new business initiatives, ROI analysis, and business planning.

"At Aventis Pharma, we are relentless in pursuing more efficient, more consistent, and more productive business practices," said Thierry Soursac, M.D., Ph.D., executive vice president and head of Global Commercial Operations, Aventis Pharma. "Technology, including Siebel eBusiness Applications, is a powerful tool for improving our customer management and standardizing relevant processes worldwide."

Siebel ePharma 7 leverages the breadth and depth of the Siebel 7 platform, including Siebel Smart Web Architecture -- the industry's first and only zero-footprint Web architecture that provides high levels of interactivity previously available only from Windows desktop applications. Prebuilt with deep pharmaceutical industry functionality, Siebel ePharma reduces total cost of ownership by eliminating many of the costs associated with customization.

About Siebel Systems

Siebel Systems, Inc. is the world's leading provider of eBusiness applications software. Siebel Systems provides an integrated family of eBusiness applications software enabling multichannel sales, marketing, and customer service systems to be deployed over the Web, call centers, field, reseller channels, retail, and dealer networks. Siebel Systems' sales and service facilities are located in more than 37 countries. For more information, please visit Siebel Systems' Web site at www.siebel.com.

Except for the historical information contained herein, this press release contains forward-looking statements that involve risks 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.

Note to Editors: 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.