A method of performing contention resolution associated with a random access procedure. The method according to one embodiment includes transmitting, by the mobile communication terminal, an uplink message containing a cell-radio network temporary identity (C-RNTI) and starting a contention resolution timer; receiving, by the mobile communication terminal, a physical downlink control channel (PDCCH) transmission; and considering, by the mobile communication terminal, a contention resolution successful and stopping the contention resolution timer if a specific condition is satisfied. The mobile communication terminal considers the contention resolution successful and stops the contention resolution timer if the PDCCH transmission is addressed to the C-RNTI and the random access procedure is initiated by a downlink (DL) data arrival. The mobile communication terminal considers the contention resolution successful and stops the contention resolution timer if the PDCCH transmission is addressed to the C-RNTI and contains an uplink (UL) grant.