Investor Inquiries Cindy Klimstra Vice President, Investor Relations 847.968.0268 cklimstra@cdw.com Media Inquiries Gary Ross Sr. Manager, Corporate Communications 847.371.5048 garyross@cdw.com CDW'S Average Daily Sales Increase 6.8 Percent in May 2006 VERNON HILLS, Ill. - June 9, 2006 - CDW Corporation (NASDAQ: CDWC), a leading provider of technology products and services to business, government and education, today announced average daily sales for May 2006 were $25.057 million, an increase of 6.8 percent compared to average daily sales of $23.459 million for May 2005. Total sales for May 2006 were $551.3 million, an increase of 11.9 percent compared to total sales of $492.6 million for May 2005. There were 22 billing days in May 2006 and 21 billing days in May 2005. Both the corporate and public sector segments grew average daily sales in May 2006. The public sector segment achieved 15.0 percent growth on an average daily basis and the corporate sector segment achieved 3.4 percent growth on an average daily basis. As previously announced, the Company completed the geographic realignment of its corporate sector segment in March 2006. Approximately 53,000 accounts consisting predominantly of medium and large business customers with 100 or more employees were transitioned during March 2006 and April 2006. The transition process was complete as of May 1, 2006. Account managers impacted by the geographic realignment have continued to make progress in establishing and building relationships with customers whose accounts were transitioned. Expected advantages from the geographic realignment include the enhanced ability to serve customers, drive new business, maximize account coverage, create additional ownership and accountability for the medium and large business sales teams, and align geographically with the Company's vendor and service partners. Product categories that achieved the strongest year-over-year unit volume growth for the month on an average daily basis included notebook CPUs, server CPUs, software, data storage, video, memory, and input devices. The Company plans to announce June 2006 sales and second quarter earnings on Wednesday, July 19, 2006. June 2005 had 22 billing days and June 2006 will have 22 billing days. Forward Looking Statement Any forward-looking statements contained in this release are based on the Company's beliefs and expectations as of the date of this release and are subject to certain risks and uncertainties which may have a significant impact on the Company's business, operating results or financial condition. Should any risk or uncertainty materialize, or should underlying assumptions prove incorrect, actual results or outcomes may vary materially from those described in forward-looking statements. Factors affecting the Company's business and prospects are discussed in the Company's filings with the Securities and Exchange Commission. 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 4,350 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, CDWG.com Web site and macwarehouse.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.