News Release-- April 17, 2003

CSC Joint Venture DynPort Complete Phase 1 Smallpox Vaccine Trial

EL SEGUNDO, Calif., April 17, 2003 – Computer Sciences Corporation (NYSE: CSC) announced today that DynPort Vaccine Company LLC (DVC), a joint venture between CSC and Porton International, a leading vaccine development company focused on biodefense vaccines, has completed Phase I testing of the safety and immunogenicity of an improved cell-cultured smallpox vaccine (CCSV).

In this trial, 100% of 350 volunteers exhibited a positive response to either the CCSV or the historic calf lymph-produced smallpox vaccine (Dryvax). However, the incidence of vaccine-related fatigue, application site rash, increased temperature, headache, lymphangitis and nausea was at least 8% less common for volunteers receiving CCSV than Dryvax. DVC is a biopharmaceutical development company dedicated to the development and licensure of safe and efficacious biodefense vaccines for the Department of Defense (DoD) through the Joint Vaccine Acquisition Program (JVAP). This is accomplished through the design and implementation of strategies for advanced development by partnering with government and industry.

“Protection against potential future biological attacks continues to be a key concern of our nation’s leaders,” said DVC President Terry Irgens. ‘The availability of adequate stocks of effective and safe smallpox vaccine that meets modern manufacturing standards is of paramount importance. At DVC, our mission remains the development and manufacture of biodefense vaccines to protect the nation’s operating forces and citizens. We do this by applying modern technologies and our established expertise to the development of FDA-compliant vaccines.”

DVC's new smallpox vaccine, derived from the historic New York Board of Health strain that was licensed in the US and previously used by the DoD, is produced using stringent modern manufacturing methods and grown in the highly characterized MRC-5 human lung cells.

The Phase I trial of CCSV was recently completed at the University of Kentucky’s Chandler Medical Center. The trial focused on the safety and immunogenicity of CCSV in vaccinia-naive and vaccinia-experienced healthy volunteers. The double-blind study randomized 350 volunteers into one of five cohorts. The first four cohorts were volunteers randomly assigned to receive either undiluted CCSV or Dryvax. The fifth study cohort provided preliminary information on the safety and efficacy of CCSV dilutions of up to one part per fifty. In this cohort, all but one of 100 volunteers developed a positive response to vaccination. This volunteer received a 1:25 dilution of CCSV.

Porton International, Inc., is a member of the Beaufour-Ipsen Group of companies.

About CSC

Founded in 1959, Computer Sciences Corporation is one of the world’s leading information technology (IT) services companies. CSC’s mission is to provide customers in industry and government with solutions crafted to meet their specific challenges and enable them to profit from the advanced use of technology.

With approximately 90,000 employees, including more than 26,000 from the company’s March 7, 2003 acquisition of DynCorp, CSC provides innovative solutions for customers around the world by applying leading technologies and CSC’s own advanced capabilities. These include systems design and integration; IT and business process outsourcing; applications software development; Web and application hosting; and management consulting. Headquartered in El Segundo, Calif., CSC reported revenue of $11.3 billion for the 12 months ended Dec. 27, 2002. For more information, visit the company’s Web site at www.csc.com.

All statements and assumptions in this press release that do not directly and exclusively relate to historical facts constitute "forward-looking statements" within the meaning of the Safe Harbor provisions of the Private Securities Litigation Reform Act of 1995. These forward-looking statements represent the current expectations and beliefs of Computer Sciences Corporation, but are subject to risks, uncertainties and other factors that could cause actual results to differ materially from the results described in such statements. For a description of these factors, see the section titled "Management's Discussion and Analysis of Financial Condition and Results of Operations; Forward-Looking Statements" in CSC's Quarterly Report on Form 10-Q for the fiscal quarter ended December 27, 2002.