Costco Companies, Inc. Reports Recent Sales Results and Appoints New Board Member.

ISSAQUAH, Wash.--(BUSINESS WIRE)--May 6, 1999--

Costco Companies, Inc., (the "Company") (Nasdaq:COST) today reported net sales of $2.02 billion for the four weeks ended May 2, 1999, an increase of 14 percent from $1.77 billion in the same four-week period of the prior fiscal year. On a comparable warehouse basis, that is warehouses open at least a year, sales increased 10 percent. This year's four-week period included 28 days of sales compared to 27 days during the year-earlier period, reflecting the timing of Easter, which positively impacted sales by approximately 2 percent.

For the first thirty-five weeks of its 1999 fiscal year ended May 2, 1999, the Company reported net sales of $17.77 billion, an increase of 13 percent from $15.78 billion during the first thirty-five weeks of the prior fiscal year. Comparable warehouse sales for this year-to-date period increased 9 percent over the prior year's level.

Costco currently operates 288 warehouses, including 218 in the United States, 58 in Canada, seven in the United Kingdom, three in Korea, one in Taiwan, and a recently opened warehouse in Hisayama, Japan; and 16 additional warehouses in Mexico with a joint venture partner. The Company also operates Costco Online, an electronic commerce web site, at www.costco.com. Expansion plans for the remainder of its 1999 fiscal year, ending August 29, 1999, include opening an additional 12 to 14 new warehouses (including four relocations of existing warehouses to larger and better-located facilities).

The Company also announced that Dr. Benjamin S. Carson, Sr., M.D., has joined its Board of Directors. Dr. Carson has been Director of Pediatric Neurosurgery at Johns Hopkins Medical Institutions since 1984 and holds appointments in the departments of neurosurgery, oncology, plastic surgery and pediatrics at the Hopkins School of Medicine. Dr. Carson, a native of Detroit, earned his undergraduate degree at Yale University in 1973 and his medical degree from the University of Michigan School of Medicine in 1977. Dr. Carson is a member of the Board of Directors of Kellogg Company and is a Fellow of the Yale Corporation, the governing body of Yale University.