A method and apparatus for supporting a closed subscriber group (CSG) service is provided. The apparatus includes a memory to store CSG subscription information and a processor operatively coupled to the RF unit and memory to implement a radio interface protocol. The processor accesses a base station (BS), transmits the CSG subscription information to the BS, receives an access mode from the BS where the access mode is determined based on the CSG subscription information, and negotiates with the BS with regard to a CSG service if the access mode supports a CSG to which the apparatus belongs.