Design of a sliding mode control algorithm with efficient online compensation for robot manipulator is studied for robust and accurate tracking of the desired trajectories. The sliding mode tracking control uses a disturbance observer to eliminate the chattering problem that exists in conventional sliding mode control under modeling error and payload uncertainty. The proposed sliding mode control is presented in two theorems. The bounded stability of the proposed control method is proved. The efficiency of the control algorithm has been demonstrated by simulations for position tracking control of a robot subject to parameter and payload uncertainties.>