This paper presents a robust discrete-time control system design for a binary distillation column. A twentieth order discrete linear multivariable model is used to design several controllers That achieve pole clustering for the distillation column while satisfying various physical constraints. A performance measure combining quantitative robustness and disturbance rejection measures is minimized subject to the parameter inequality constraints to obtain the optimum design. Although a numerical solution of the design equations is unavoidable, the design equations for the distillation column are obtained analytically providing insight into the design methodology.