A method of performing a random access procedure in a wireless communication system is provided. The method includes transmitting a random access preamble, and monitoring a downlink control channel in a transmission time interval (TTI) window for a random access response, the TTI window comprising a plurality of TTIs, wherein a TTI is an interval to search a random access-radio network temporary identity (RA-RNTI) transmitted on the downlink control channel and monitoring the downlink control channel for the random access response is stopped when the random access response including an random access preamble identifier corresponding to the transmitted random access preamble is received.