A method and apparatus are provided for transmitting a data frame using channel bonding in a wireless local area network in which high throughput (HT) stations and legacy systems coexist. The method includes adding a legacy format physical layer header including information, which indicates that a medium is being used while a frame exchange sequence is performed with respect to the HT format data frame, to the HT format data frame, transmitting the HT format data frame with the physical layer header by using channel bonding, and broadcasting the legacy format CF-End frame through a plurality of channels used in the channel bonding. Accordingly, after a frame exchange sequence is completed, the legacy stations which use channels used in the channel bonding can participate in a fair contention for medium access.