Abstract: The problem of sliding mode output feedback control for uncertain discrete systems was investigated. The uncertainty of the discrete system was assumed to be mismatched, with an unknown norm bound. A dead-zone adaptive law was designed to identify the unknown bound online. The discrete sliding mode controller was designed based on the multirate output sampling theory. The discrete system is asymptotically stable with the proposed controller. Multirate output sampling is achieved by setting the output signals in a faster sample rate than that of the input signals, through relevant calculation, the current system states can be evaluated from the inputs at the previous time instance and the current outputs. Finally, a numerical example is provided to demonstrate the effectiveness of the proposed control strategy.