Please direct your media and public relations inquiries to: mediarelations@cdw.com 800-800-4CDW CDW To Release Second Quarter Results On July 20, 2004 VERNON HILLS, Ill. - July 13, 2004 - CDW Corporation (NASDAQ: CDWC) will release its second quarter 2004 results and June 2004 sales on Tuesday, July 20, 2004, at 7:30 a.m., ET / 6:30 a.m. CT. On July 20, 2004, at 8:30 a.m. ET / 7:30 a.m. CT, management will review these results during a conference call. This conference call will be available via live Webcast – in listen-mode only – on the Company's Web site at CDW.com. An audio replay of the call will be available approximately two hours after the event on CDW.com until July 30, 2004. About CDW CDW® (Nasdaq: CDWC), ranked No. 376 on the FORTUNE 500, is a leading provider of technology products and services for business, government and education. CDW is a principal source of technology from top name brands such as APC, Apple, Cisco, HP, IBM, Microsoft, Sony, Symantec, Toshiba and ViewSonic. CDW distributes contracts to end users for customized and standardized on-site services supplied directly by providers such as HP Services and Unisys and for training programs provided by firms such as KnowledgeNet and Productivity Point International. CDW was founded in 1984 as a home-based business and today employs approximately 3,700 coworkers. In 2003, the company generated net sales of approximately $4.7 billion. CDW's direct model offers one-on-one relationships with knowledgeable account managers; purchasing by telephone, fax, the company's award-winning CDW.com Web site, customized CDW@work™ extranets, CDWG.com Web site and macwarehouse.com Web site; custom configured solutions and same day shipping; and pre- and post-sales technical support, with more than 100 factory-trained and A+ certified technicians on staff. Additional information can be found by visiting CDW.com.