A method and apparatus are provided for controlling an active state in a mobile communication system. The method includes receiving, from a base station, information related to a starting position of an active state and information related to a length of a first timer; deriving the starting position of the active state based on the information related to the starting position; starting the first timer set to the length of the first timer and entering the active state at the derived starting position; terminating the active state if control data indicating a transmission of user data is not received until the first timer expires; extending a period of the active state if the control data is received before the first timer expires; and terminating the active state based on a control signal indicating a termination of the active state.