Investor Inquiries Cindy Klimstra Vice President, Investor Relations 847-968-0268 Media Inquiries Gary Ross Sr. Manager, Corporate Communications 847-371-5048 CDW to Release Third Quarter of 2006 Results on October 18, 2006 VERNON HILLS, Ill. - October 11, 2006 - CDW Corporation (NASDAQ: CDWC) will release its third quarter of 2006 results and September 2006 sales results on Wednesday, October 18, 2006, at 8:30 a.m. ET / 7:30 a.m. CT. On October 18, 2006, at 9:30 a.m. ET / 8:30 a.m. CT, management will review these results during a conference call. The conference call will be available via live webcast in listen-only mode on the Company's web site at www.cdw.com/investor. An audio replay of the call will be available approximately two hours after the event on www.cdw.com/investor for approximately two weeks. About CDW CDW®, ranked No. 343 on the FORTUNE 500, is a leading provider of technology solutions for business, government and education. CDW is a principal source of technology products and services including top name brands such as Adobe, Apple, Cisco, HP, IBM, Lenovo, Microsoft, Sony, Symantec and Toshiba. CDW was founded in 1984 and employs approximately 4,450 coworkers. In 2005, the company generated sales of $6.3 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, and CDWG.com web site; custom configured solutions and same day shipping; and pre- and post-sales technical support, with approximately 120 factory-trained and A+ certified technicians on staff. For more information about CDW: Visit CDW on the Internet at http://www.cdw.com. Contact CDW Investor Relations via the Internet at investorrelations@cdw.com or by telephone at 847-419-6328.