A method and apparatus for performing a random access procedure in a wireless communication system is provided. In one embodiment, a user equipment (UE) determines a required amount of repetitions for uplink transmissions during a random access procedure, and performs repetitions for uplink transmissions based on the determined required amount of repetitions for uplink transmissions. The uplink transmissions may include transmission of preambles which are grouped. In another embodiment, a UE configures a communication windows for lost-cost machine-type communication (MTC) UE, and performs a random access procedure through the configured communication window.