A method of transmitting a sounding reference signal (SRS) in a wireless communication system is discussed. The method according to one embodiment includes receiving a first UE-specific configuration indicating possible subframes for aperiodic SRS transmission via a radio resource control (RRC) signaling, wherein the possible subframes are periodically configured; receiving a physical downlink control channel (PDCCH) signal including request information of requesting aperiodic SRS transmission; and transmitting at least one SRS one time in response to the request information within the possible subframes.