The present invention relates to a method and apparatus for transmitting/receiving data in a wireless communication system. According to one aspect of the present invention, a data receiving method is provided wherein a mobile station in a wireless communication system uses a frame including a first subframe in which a physical downlink shared channel (hereinafter, referred to as “PDSCH”) includes a first cyclic prefix (hereinafter, referred to as “CP”) and a second subframe in which the PDSCH includes a second CP, wherein the data receiving method comprises a step in which the mobile station receives information on the length of the first CP from a base station, receives data from the base station through the first subframe, and removes the CP of the data using the information on the length of the first CP. The first CP and the second CP have different lengths.