A random access method in a wireless communication system and an apparatus therefor are provided. A method for performing two-step random access in user equipment (UE) includes transmitting a first message to a base station (BS), the first message including a medium access control (MAC) packet data unit (PDU) that includes a common control channel (CCCH) service data unit (SDU) or a cell radio network temporary identifier (C-RNTI), and a random access preamble, monitoring a physical downlink control channel (PDCCH) for a second message from the BS within a configured time window, the second message corresponding to the first message, and determining whether the two-step random access is successful based on a result of the monitoring.