Costco November Same-Store Sales Up 5%

Costco Wholesale Corporation reported net sales of $4.08 billion for the four weeks ended November 28, 2004, an increase of 7% from $3.80 billion in the same four-week period of the prior fiscal year.

For the first 13 weeks of its 2005 fiscal year ended November 28, 2004, the Company reported net sales of $12.40 billion, an increase of 10 percent from $11.29 billion during the similar 13-week period of the prior fiscal year.

Comparable sales for the 4-week and 13-week periods ended November 28, 2004, were as follows:

                                   4 Weeks             13 Weeks
                             ------------------- ---------------------
US                                   6%                   7%
International                        3%                   7%

Total Company                        5%                   7%
                             =================== =====================

Reported net sales were reduced by the implementation of Emerging Issues Task Force Issue No. 03-10 (“EITF 03-10”), “Application of Issue No. 02-16 by Resellers to Sales Incentives Offered to Consumers by Manufacturers,” which was effective at the beginning of the Company’s fiscal 2004 third quarter, February 16, 2004. Had sales for the 4-week and 13-week periods last year been reported under EITF 03-10, total Company reported net sales increases would have been 8 percent and 11 percent, respectively, and total Company comparable sales increases would have been 6 percent and 8 percent, respectively.