This paper proposes a novel control algorithm for linear discrete time uncertain input delay systems using infrequent output observations i.e, periodic output feedback technique. First, the uncertain delayed system, with a constant delay and bounded uncertainty is converted to an equivalent delay free system using a predictor. It has been shown that, when the output of the uncertain predicted system is sampled slower than the input, there exists a discrete-time quasi sliding mode. Since the proposed algorithm is based on output feedback, it is more practical in comparison to state feedback based control algorithms. The simulation results demonstrate the efficacy of the proposed algorithm. © 2013 IEEE.