Costco Wholesale Corporation Reports July Sales Results.

ISSAQUAH, Wash. -- Costco Wholesale Corporation (Nasdaq: COST) today reported net sales of $4.02 billion for the four weeks ended July 31, 2005, an increase of 8 percent from $3.71 billion in the same four-week period of the prior fiscal year. This year's four-week period included 27 days of sales compared to 28 days for the comparable four-week period last year, reflecting the timing of the Fourth of July holiday. This calendar shift negatively impacted reported net sales and comparable sales by approximately 3-4 percent.

For the first 48 weeks of its 2005 fiscal year ended July 31, 2005, the Company reported net sales of $47.78 billion, an increase of 10 percent from $43.51 billion during the similar 48-week period of the prior fiscal year.

Comparable sales for the 4-week and 48-week periods ended July 31, 2005, were as follows:

4 Weeks                 48 Weeks
                     ----------------------- -------------------------
US                              4%                       6%
International                  12%                      11%

Total Company                   5%                       7%
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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# 5076011). This recorded message will be available today through 7:00 PM (PDT) on Friday, August 5, 2005.

Costco currently operates 458 warehouses, including 337 in the United States and Puerto Rico, 65 in Canada, 16 in the United Kingdom, five in Korea, four in Taiwan, five in Japan and 26 in Mexico. The Company also operates Costco Online, an electronic commerce web site, at www.costco.com and at www.costco.ca in Canada. The Company plans to open two additional new warehouses prior to the end of its fiscal year 2005, on August 28, 2005.

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.