A method for performing a handoff between an asynchronous base station and a synchronous base station. The method includes the steps of: a) setting at least one common channel between the synchronous base station and a mobile station; b) determining whether there is an asynchronous base station to be handed off in neighbor asynchronous base stations based on monitoring information of the neighbor asynchronous base stations; c) if there is no asynchronous base station, requesting a handoff to the synchronous base station and receiving a compressed mode message through the common channel; d) selecting a synchronous base station to be handed off based on the compressed mode message; and e) performing the handoff from the asynchronous base station to the synchronous base station.