Mail Stop 3561
								January 30, 2005
Mr. John A. Edwardson
Chief Executive Officer
CDW Corporation
200 N. Milwaukee Ave.
Vernon Hills, IL



      Re:	CDW Corporation
Form 10-K for the Fiscal Year Ended December 31, 2004
		File No. 000-21796



Dear Mr. Edwardson:

      We have reviewed your response letter dated December 9, 2005
and have the following comment.  Please be as detailed as
necessary
in your explanations.  We may ask you to provide us with
information
so we may better understand your disclosure.  After reviewing this
information, we may raise additional comments.

Management`s Discussion and Analysis of Financial Condition and
Results of Operations, page 15

Revenue Recognition, page 15

1. We note your response to comment 1 from our letter dated
December
9, 2005.  Please provide us with the following additional
information:

* The amount of monthly revenue attributable to product shipped to
customers using other carrier methods outside the five methods
that
have the largest dollars of sales.  Please also quantify the
amount
of monthly revenue attributable to product shipped via electronic
delivery and manufacturer or third-party shipments made directly
to
customers.  Please provide a summary by delivery method for each
month for the year ended December 31, 2004;

* On what basis you have assumed an average delivery time of three
business days for manufacturer or third-party shipments made
directly
to the customer as opposed to two business days for your customer
shipments;

* On what basis you assume a delivery time of one business day for
your electronic delivery of products (i.e. software);

* Whether you perform your calculation of weighted average
customer
delivery time for the five delivery methods that have the largest
dollars of sales using the sales amounts from your sample of
shipments selected or your actual sales amounts attributable to
each
shipping method for the given week selected.  If you use the sales
amounts from your sample of shipments, please tell us how much
your
calculation of weighted average shipment time would have been
altered
had you used actual sales amounts;

* Your calculations and analyses that support the December 31,
2004
deferred revenue balance that estimates the value of products that
have shipped but which have not been received by the customer.

* * * * *

       Please respond to this comment within 10 business days or
tell
us when you will provide us with a response.  Please furnish a
cover
letter that keys your responses to our comment and provides any
requested information.  Detailed cover letters greatly facilitate
our
review.  Please understand that we may have additional comments
after
reviewing your response to our comment.

	You may contact Scott Ruggiero at (202) 551-3331 if you have
questions regarding comments on the financial statements and
related
matters.  Please contact me at (202) 551-3716 with any other
questions.


Sincerely,


William Choi
Branch Chief


Mr. John A. Edwardson
CDW Corporation
January 30, 2006
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