Costco Wholesale Corporation operates an international chain of membership warehouses, under the "Costco Wholesale" name, that carry quality, brand name merchandise at substantially lower prices than are typically found at conventional wholesale or retail outlets. The warehouses are designed to help small-to-medium-sized businesses reduce costs in purchasing for resale and for everyday business use. Individual Members may also purchase for their personal needs.

Costco Wholesale Corporation began operations in 1983 in Seattle, Washington. In October 1993, Costco merged with The Price Company, which had pioneered the membership warehouse concept in 1976, to form Price/Costco, Inc., a Delaware corporation. In January 1997, non-warehouse assets were spun off to Price Enterprises, Inc., and the company changed its name to Costco Companies, Inc. On 30th August, 1999, the Corporation re-incorporated from Delaware to Washington and changed its name to Costco Wholesale Corporation, which trades on the NASDAQ under the symbol 'COST'. Costco world headquarters are located in Issaquah, Washington, The U.K. Home Office is located in Watford, Hertfordshire.

Costco's warehouses present one of the largest and most exclusive product category selections to be found under a single roof. Categories include catering supplies, confectionery, appliances, television and media, automotive supplies, tyres, toys, hardware, sporting goods, jewellery, watches, cameras, books, housewares, apparel, health and beauty aids, tobacco, furniture, office supplies and office equipment. Costco is known for carrying top quality national and regional brands, at prices consistently below traditional wholesale or retail outlets.

Members can also shop for private label Kirkland Signature products, guaranteed to be high quality products, including juice, cookies, coffee, nuts, housewares, luggage, appliances, clothing and detergent.