CDW 10-K 2003 FY Annual report

EXHIBIT 32.2

CERTIFICATION PURSUANT TO SECTION 1350 OF CHAPTER 63
OF TITLE 18 OF THE UNITED STATES CODE

     I, Barbara A. Klein, the chief financial officer of CDW Corporation, (“CDW”), certify that (i) the Annual Report on Form 10-K for the year ended December 31, 2003 (the “10-K”) of CDW fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 and (ii) the information contained in the 10-K fairly presents, in all material respects, the financial condition and results of operations of CDW.

  /s/ Barbara A. Klein

  Barbara A. Klein

  Senior Vice President and Chief Financial Officer

  CDW Corporation

  March 11, 2004