An adaptive robust control scheme with valve dead-zone compensation was proposed for pneumatic position servo systems. The controller employed the on-line recursive least squares estimation to reduce parametric uncertainties, and utilized a robust control method to attenuate the effects of parameter estimation errors, unmodelled dynamics and disturbance. Thus, a good transient with precision motion trajectory tracking of pneumatic cylinders was guaranteed. The standard projection type adaption law was adopted to achieve a complete separation of the estimator design and the robust control law design. Since the system model uncertainties were unmatched, the recursive backstepping technology was applied to design the robust controller. Extensive comparative experimental results were presented to illustrate the effectiveness of the proposed controller and its performance robustness to parameter variations and sudden disturbance. 