COSTCO WHOLESALE CORPORATION ANNOUNCES

QUARTERLY CASH DIVIDEND

ISSAQUAH, Wash., January 24, 2013 - Costco Wholesale Corporation (“Costco” or the “Company”) (Nasdaq: COST) today announced that its Board of Directors declared a quarterly cash dividend on Costco common stock of $.275 per share. The quarterly dividend is payable February 22, 2013, to shareholders of record at the close of business on February 8, 2013.

Costco currently operates 622 warehouses, including 448 in the United States and Puerto Rico, 85 in Canada, 32 in Mexico, 23 in the United Kingdom, 13 in Japan, nine in Taiwan, nine in Korea and three in Australia. Costco also operates electronic commerce web sites, at www.costco.com (U.S.), www.costco.ca (Canada), and www.costco.co.uk (United Kingdom).

Certain statements contained in this document 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 costs), energy, and certain commodities, 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.

Issaquah Home Office • 999 Lake Drive • Issaquah, WA 98027-5367 • (425) 313-8100