Sales at comparable Costco stores were flat in January though industry analysts were expecting a slight uptick.
Analysts polled by Thomson Reuters predicted a 1.2 percent rise in sales at stores open at least a year.
Sales from stores open at least a year are a key indicator of a retailer's health because it excludes volatility from recently opened or closed locations.
Like other U.S. companies that operate abroad, sales at home were fine, but a slowing global economy proved to be a drag.
Like-store sales rose 2 percent in the U.S., but fell 4 percent internationally.
Stripping out the impact of lower gasoline prices and foreign exchange fluctuations, sales at stores open at least a year rose 7 percent overall, up 7 percent in the U.S. and up 6 percent overseas.
Total revenue for the four weeks ended Feb. 1 climbed 2 percent to $8.16 billion.
For the year, sales at stores open at least a year increased 3 percent, up 5 percent in the U.S. and down 1 percent internationally.
Excluding the impact of lower gasoline prices and foreign exchange fluctuations, the figure climbed 7 percent at home and abroad.
Total revenue rose 6 percent to $49.01 billion.
Costco expects to report its second-quarter financial results and its February sales results on March 5.
Costco Wholesale Corp., which is based in Issaquah, Washington, runs 671 warehouses, including 474 in the U.S. and Puerto Rico, 88 in Canada, 34 in Mexico, 26 in the U.K., 20 in Japan, 11 in Korea, 10 in Taiwan, seven in Australia and one in Spain.