Disclosed are a system and a method for optimizing a handover process in a mobile broadband wireless access system. The method performs handover in a mobile communication system including a mobile subscriber station, a serving base station currently providing service to the mobile subscriber station, and at least one neighbor base stations adjacent to the serving base station. The method includes the steps of receiving a handover request from the mobile subscriber station by the serving base station; instructing the mobile subscriber station to perform handover by the serving base station in response to the handover request from the mobile subscriber station and performing by the mobile subscriber station a network reentry process for fast handover in accordance with information included in a handover instruction from the serving base station.