A method for performing effective handover (HO) in a broadband wireless access system is disclosed. The method for controlling a mobile station (MS) to perform handover in a broadband wireless access system includes receiving a first message including at least one of first index information and second index information from a serving base station (SBS), wherein the first index information indicates a subframe to which an additional ranging opportunity for the mobile station (MS) is allocated from a target base station (TBS) and the second index information indicates a frame to which the additional ranging opportunity is allocated, and transmitting a ranging code to the target base station (TBS) through the additional ranging opportunity indicated by the first index information and the second index information.