A handover method and apparatus in a mobile communication system are provided to allow a terminal to transmit a status report to a source ENB(Evolved Node B) immediately before handover occurs, and not retransmit RLC PDU(Packet Data Unit)s, which have not received a positive acknowledgement signal yet, thereby minimizing a data amount from the source ENB to a target ENB. A measurement controller(1205) controls measurement of the size of a reception signal of neighbor cells. A radio resource controller(1210) generates a measurement result received from the measurement controller(1205) as a message and transmits the same to a base station of a source cell. Before performing handover to a target cell, a radio link controller(1220) receives a status report command from the radio resource controller(1210), generates a status report message, and transmits it to the base station of the source cell. The measurement controller(1205) determines whether the measurement result report satisfies handover conditions previously agreed with the base station of the source cell. The radio resource controller transmits the status report command to the radio link controller(1220) according to determination of the measurement controller(1205).