A method and apparatus for determining an ACK frame appropriate for a wireless local area network (LAN) environment where high throughput stations and legacy stations with different data transmission capabilities coexist to acknowledge the receipt of a transmission frame. The method and apparatus enable each station to access a medium normally in the wireless LAN environment and complement a carrier sensing method. The method includes determining types of stations on a wireless local area network, determining the ACK frame for acknowledging the receipt of the transmission frame on the wireless local area network according to the result of determination, and notifying a corresponding station on the wireless local area network of the determined ACK frame.