A key sales figure rose both in the U.S. and abroad, but its earnings fell short of Wall Street expectations. Its shares slipped in premarket trading Thursday.
Costco's stores offer members the ability to buy items in bulk at low prices.
Net income for the 12 weeks ended May 11 rose 3 percent to $473 million, or $1.07 per share. That compares with net income $459 million, or $1.04 per share.
Analysts expected $1.09 per share, according to FactSet.
Revenue rose 7 percent to $25.79 billion from $24.08 billion last year. Analysts expected $25.68 billion.
Revenue in stores open at least one year rose 5 percent in the U.S. and 3 percent internationally. Excluding gas prices and foreign currency fluctuation, the figure rose 6 percent in the U.S. and 8 percent internationally.
Costco, based in Issaquah, Washington, operates 655 warehouses, including 464 in the United States and Puerto Rico, 87 in Canada, 33 in Mexico, 25 in the United Kingdom, 19 in Japan, 10 in Taiwan, 10 in Korea, six in Australia, and one in Spain.
Its shares fell $1.24, or 1.1 percent, to $113 in premarket trading about 2 1/2 hours before the market open.