Analysts surveyed by Thomson Reuters forecast a 3.2 percent rise.
This figure is a key indicator of a retailer's health. It excludes results from stores recently opened or closed.
In the U.S. the metric increased 5 percent. It rose 2 percent overseas.
Removing higher gas prices and foreign currency fluctuation, sales at stores open at least a year still climbed 5 percent for the total company and for U.S. locations. Internationally, the figure increased 7 percent.
Total revenue for the four weeks ended May 4 rose 7 percent to $8.56 billion.
Costco Wholesale Corp. said that there was one less selling day in the period which accounts for a shift in the timing of Easter. The wholesale club operator said that the later Easter this year hurt its total revenue and same-store sales by 1.5 percent to 2 percent.
For the year to date, the Issaquah, Washington-based company said that sales at stores open at least a year rose 3 percent. The metric rose 4 percent in the U.S. and edged up 1 percent abroad.
Excluding higher gas prices and foreign currency fluctuation, sales at stores open at least a year increased 5 percent. It rose 5 percent in the U.S. and rose 7 percent overseas.
Total revenue for the year to date increased 6 percent to $73.21 billion.
Costco expects to report its fiscal third-quarter financial results on May 29. The company currently runs 652 warehouses, including 463 in the U.S. and Puerto Rico, 87 in Canada, 33 in Mexico, 25 in the U.K., 19 in Japan, 10 in Taiwan, 10 in Korea and five in Australia.