Costco Wholesale Corporation Reports March Sales Results

| Source: Costco Costco

ISSAQUAH, WA -- (MARKET WIRE) -- April 12, 2007 -- Costco Wholesale Corporation ("Costco") (NASDAQ: COST) today reported net sales of $5.94 billion for the month of March, the five weeks ended April 8, 2007, an increase of 11 percent from $5.37 billion in the same five-week period last year.

For the first thirty-two weeks of its reporting period ended April 8, 2007, the Company reported net sales of $38.11 billion, an increase of 9 percent from $35.02 billion during the similar thirty-two-week period of the prior year. These year-to-date net sales results include the $224 million adjustment to the sales returns reserve previously reported in the fiscal 2007 second quarter results.

Comparable sales for the 5-week retail-reporting month of March and the 32-week retail-reporting period of September through March are as follows: 

                                5 Weeks    32 Weeks
                              ----------  ----------

             US                       5%          4%
             International            7%          8%

             Total Company            6%          5%
                              ==========  ==========
This year's five-week period included 34 days of sales compared to 35 days last year, reflecting the timing of Easter. This calendar shift impacted sales negatively by approximately one to two percent.

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 5557155). This recorded message will be available today through 5:00 p.m. (PT) on Friday, April 13, 2007.

Costco currently operates 508 warehouses, including 374 in the United States and Puerto Rico, 71 in Canada, 19 in the United Kingdom, five in Korea, four in Taiwan, five in Japan and 30 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 ten to eleven new warehouses prior to the end of its 52-week 2007 fiscal year on September 2, 2007.

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 those 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, 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.

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