This paper describes the position control of a cylindrical pneumatic actuator using sliding mode control approach. It is difficult task to obtain an accurate mathematical model of pneumatic drives due to significant system nonlinearities, caused by air compressibility, friction effects and variations of process parameters with time. This control strategy can be used to realize the control system requirements achieving a reasonable positioning accuracy. The effectiveness of the proposed control strategy is confirmed by experiments using the existent electro-pneumatic servo system that consists of a rodless cylinder controlled by a proportional servo valve.