Costco's sales at its stores open at least a year rose 4 percent in October, beating Wall Street's expectations.
Analysts expected a 3.6 percent rise, according to Thomson Reuters.
Sales at stores open at least a year is a key gauge of a retailer's health because it excludes results from stores recently opened or closed.
In the U.S., sales at stores open a year rose 6 percent in the month. Sales at the warehouse club operator's international stores were flat.
Excluding lower gasoline prices and foreign currency fluctuations, sales at stores open at least a year increased 7 percent for the total company and for U.S. stores. Internationally, the figure rose 6 percent.
Total revenue rose 7 percent to $8.73 billion in the four weeks ending November 2 from $8.15 billion in the same month a year ago.
For the nine weeks ending November 2, the company's sales at stores open at least a year increased 4 percent. The figure climbed 6 percent in the U.S. and 1 percent abroad.
Excluding higher gasoline prices and foreign currency fluctuations, sales at stores open at least a year rose 6 percent for the total company. In the U.S. the metric increased 7 percent. It climbed 6 percent overseas.
Total revenue for the period increased 7 percent to $19.30 billion from $18.01 billion a year ago.
Costco Wholesale Corp., based in Issaquah, Washington, currently runs 666 warehouses around the world and plans to open up to an additional five new warehouses before the end of the year.