A random access channel (RACH) management method performed by a user equipment (UE) in a mobile communication system and an apparatus are provided. The method includes receiving, from a network, a signal indicative of a resolution of contention in a RACH procedure before a contention resolution timer expires; determining, if the received signal includes a contention resolution message including a unique identifier (ID) of the UE, that the RACH procedure has been successfully completed; receiving, from the network, after the successful completion of the RACH procedure, a UE information transmit request; and transmitting, to the network, in response to receipt of the UE information transmit request, a response message including first information indicating that the contention is detected in at least one preamble transmitted for the completed RACH procedure and indicating a number of the at least one preamble in which the contention is detected.