A power controlling apparatus and method in a mobile communication system. A receiver in a mobile station multiplexes the frame reception result indicator bits for at least two traffic channels received from a transmitter in a base station, inserts the multiplexed frame reception result indicator bits in a pilot signal bit by bit, and transmits the reverse frame. Then, the transmitter extracts the pilot signal from the reverse frame, demultiplexes the frame reception result indicator bits, and performs a power control on the traffic channels based on the values of the frame reception result indicator bits.