Apparatus and method for controlling data transmission rate in a wireless communication system during handoff comprises a terminal recognizing an active set comprising a serving base station and at least one non-serving base station with respect to the terminal communicating with the network at a first data transmission rate, receiving a first rate control parameter from the serving base station and a second rate control parameter from the at least one non-serving base station, wherein the first and second rate control parameters are associated with determination of a second data transmission rate of the terminal during the handoff and determining the second data transmission rate in response to the first and the second rate control parameters, wherein the second data transmission rate is one of increased rate, decreased rate and same rate from the first data transmission rate.