Costco Wholesale Corporation reported net sales of $3.94 billion for the four weeks ended May 1, 2005, an increase of 11 percent from $3.56 billion in the same four-week period of the prior fiscal year.

For the first 35 weeks of its 2005 fiscal year ended May 1, 2005, the Company reported net sales of $34.43 billion, an increase of 10% from $31.35 billion during the similar 35-week period of the prior fiscal year.

Comparable sales for the 4-week and 35-week periods ended May 1, 2005, were as follows:

                                    4 Weeks             35 Weeks
                              -------------------- -------------------
US                                     7%                  6%
International                         16%                  11%

Total Company                          8%                  7%
                              ==================== ===================

This year's four-week period included 28 days of sales compared to 27 days last year, reflecting the timing of Easter. This calendar shift impacted sales positively by approximately 2 percent.

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. Sales for the 4-week reporting periods are on a comparable after-coupon basis; however, had sales for the 35-week year-to-date period last year been reported under EITF 03-10, the total Company reported net sales increase would have been 11 percent and the total Company comparable sales increase would have been 8 percent.