The paper presents the design of discrete-time chatter free sliding mode control for the two-time-scale full system using the slow subsystem. It has been shown that a sliding mode control designed for the slow subsystem gives similar performance for the full system. Also, the obtained state feedback based control is converted into output feedback based control using fast output sampling approach. The state computation method presented here can avoid ill-conditions in dealing with full two-time-scale system. The method is successfully illustrated by numerical example which is reported in literature. © 2008 IEEE.