The retailer, which operates 17 cash and carries in the UK, said net income rose to US$215.8 million (£123.7 million) in the first quarter to November 20, from US$193.2 million (£110.8 million) last year.
The company said its first-quarter results included about 1 cent a share in pre-tax charges, relating to damage from four Florida hurricanes.
Costco said net sales during the period rose 12 per cent to US$12.66 billion (£7.26 billion) from US$11.34 billion (£6.5 billion) the year before.
The group is accelerating its overseas expansion. Chief finance officer Richard Galanti told US stockbrokers last month: 'In the next year, we will place a little more focus on international markets - we have certainly improved our purchasing power.'