A method and a system is disclosed for controlling a sleep mode in broadband wireless access communication system. The subscriber terminals are managed by grouping the subscriber terminals in a broadband wireless access communication system, so an efficiency for controlling the sleep mode of the broadband wireless access communication system may increase. A further advantage is provided that each point of time for transmitting a paging message of each group is established differently from each other within a unit time slot for controlling the sleep mode, such that subscriber terminals are managed according to groups. Another advantage is provided that the base station can previously find subscriber terminals awaking at each point of time for transmission the paging message of each other from among subscriber terminals having the sleep mode, so an efficiency for controlling the sleep mode of the broadband wireless access communication system may increase.