Costco Wholesale Corporation Reports August, Fourth Quarter and Fiscal Year 2004 Sales Results.

ISSAQUAH, Wash. -- Costco Wholesale Corporation (Nasdaq: COST) today reported net sales of $3.65 billion for the four weeks ended August 29, 2004, an increase of 7 percent from $3.42 billion in the same four-week period of the prior fiscal year.

For the 16-week fiscal fourth quarter ended August 29, 2004, the Company reported net sales of $14.84 billion, an increase of 11 percent from $13.42 billion during last year's fiscal fourth quarter.

For the 52-week fiscal year ended August 29, 2004, the Company reported net sales of $47.15 billion, an increase of 13 percent from $41.69 billion during the prior fiscal year.

Comparable sales for the 4-week, 16-week and 52-week periods ended August 29, 2004, were as follows:

4 Weeks       16 Weeks       52 Weeks
                 ------------  ------------  --------------
US                    3%            8%              9%
International         9%            6%             14%

Total Company         4%            8%             10%
                 ============  ============  ==============

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 third quarter, February 16, 2004. Had sales for the 4-week, 16-week and 52-week periods last year been reported under EITF 03-10, total Company reported net sales increases would have been 9 percent, 12 percent and 14 percent, respectively, and Company comparable sales increases would have been 6 percent, 9 percent and 11 percent, respectively.

Additional discussion of these sales results is available on a pre-recorded telephone message. You can access the recording by dialing 1-800-642-1687 (conference ID# 9823479). This recorded message will be available today through 5:00 PM (PDT) on Friday, September 3, 2004.

The Company plans to release its operating results for the fourth quarter (16 weeks) and fiscal year 2004 (52 weeks) ended August 29, 2004 on October 7, 2004. A conference call to discuss these fourth quarter results is scheduled for 8:00 a.m. (PDT) on October 7th, and will be available via a webcast on www.costco.com (click on Customer Service, Investor Relations, Financial Releases and lastly the "Live Webcast" icon.)

Costco currently operates 441 warehouses, including 327 in the United States and Puerto Rico, 63 in Canada, 15 in the United Kingdom, five in Korea, three in Taiwan, four in Japan and 24 in Mexico. The Company also operates Costco Online, an electronic commerce web site, at www.costco.com. The Company plans to open an additional 12 to 13 new warehouses (including the relocation of three warehouses to larger and better-located facilities) prior to the end of calendar year 2004.

Certain statements contained in this release constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. For these purposes, forward-looking statements are statements that address activities, events, conditions or developments that the Company expects, or anticipates may occur in the future. Such forward-looking statements involve risks and uncertainties that may cause actual events, results or performance to differ materially from those indicated by such statements. These risks and uncertainties include, but are not limited to, domestic and international economic conditions including exchange rates, the effects of competition and regulation, consumer and small business spending patterns and debt levels, rising costs associated with employees (including health care and workers' compensation costs), conditions affecting the acquisition, development, ownership or use of real estate, actions of vendors, and other risks identified from time to time in the Company's public statements and reports filed with the SEC.