In this paper, an output feedback discontinuous controller is proposed for a class of non-linear systems to attenuate the disturbance influence on the system performance. Our main goal is to globally stabilize the non-linear system in the presence of unknown structural system uncertainties and external disturbances. Our approach consists of constructing a high gain non-linear observer to reconstruct the unavailable states, and then design discontinuous controller using a backstepping like design procedure to ensure stability of the non-linear system. The design parameters of the observer and the controller are determined in a complementary manner to ensure stability. As a result the whole system can be stabilized while internal stability of the system states is also ensured. Finally, an example is presented to show the effectiveness of the proposed scheme.