A robust teleoperation controller design methodfor an underwater manipulator is proposed considering the master and the underwater slave separately. To achieve transparency and stability for a teleoperation of an underwater manipulator in unknown environments with time-varying uncertaintiessuch as added mass, buoyancy, hydraulic drag and friction effect, an adaptive sliding mode control scheme is proposed for robust position tracking control of slave manipulator To guarantee a force transparency in the master side, disturbance observer is used as a local controllerfor compensating a friction and coupled nonlinear dynamic effects of the master manipulator Numerical simulations are performed to demonstrate the transparency and robustness of theproposed controller