Costco Wholesale Corporation Reports June Sales Results

Market Wire, July, 2008

Costco Wholesale Corporation ("Costco") (NASDAQ: COST) today reported net sales of $7.14 billion for the month of June, the five weeks ended July 6, 2008, an increase of 12 percent from $6.35 billion in the same five-week period last year.

For the first forty-four weeks of its reporting period ended July 6, 2008, the Company reported net sales of $59.84 billion, an increase of 13 percent from $53.17 billion during the similar forty-four-week period last year.

Comparable sales for the five-week and forty-four-week periods ended July 6, 2008, were as follows:

                      5 Weeks    44 Weeks
                      --------   --------
      US                 9%         6%
      International     11%        16%

      Total Company      9%         8%
                      ========   ========

The U.S. comparable sales figure includes, among other things, the effect of gasoline price inflation, with the average sales price per gallon of gasoline up 38 percent for the five-week month of June, as compared to the year-earlier June. Excluding gasoline price inflation, U.S. comparable sales would have been up 5 percent. In addition, foreign exchange rates, primarily in Canada, positively impacted international comparable sales results. On a local currency basis, international comparable sales increased 8 percent in June.

Costco currently operates 537 warehouses, including 393 in the United States and Puerto Rico, 75 in Canada, 19 in the United Kingdom, six in Korea, five in Taiwan, eight in Japan and 31 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 an additional seven to eight new warehouses (including the relocation of two warehouses to larger and better-located facilities) prior to the end of its 2008 fiscal year on August 31, 2008.

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 47689911). This recorded message will be available today through 5:00 p.m. (PT) on Friday, July 11, 2008.

Certain statements contained in this document and the pre-recorded telephone message 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, uncertainties in the financial markets, consumer and small business spending patterns and debt levels, conditions affecting the acquisition, development, ownership or use of real estate, actions of vendors, rising costs associated with employees (including health care and workers' compensation costs), rising costs associated with the acquisition of merchandise (including the direct and indirect effects of the rising cost of petroleum-based products and fuel and energy costs), geopolitical conditions and other risks identified from time to time in the Company's public statements and reports filed with the Securities and Exchange Commission.

CONTACTS: Costco Wholesale Corporation Bob Nelson 425/313-8255 Jeff Elliott 425/313-8264