A novel methodology which is convenient for the design of optimal sliding mode control for an asynchronous machine drive is developed. A suitable model of the induction machine control system, incorporating the counter EMF under field orientation, is presented.Analytic solutions for the optimal switching vector, C, and feedback matrix, L, in unit vector sliding mode control are obtained. The optimal synthesis is directly related to the desired system specifications in time domain without the necessity of solving the Riccati equation or complicated matrix equations. This greatly simplifies the conventional complicated design procedure and improves the design quality.Simulation and experimental results verify the new optimal design.