The l(i) optimal control problem is most commonly solved through a linear programming optimization approach. In this paper, we present a Q domain solution procedure and suggest when such an approach is advantageous. In the proposed method, the coefficients of Q are used as optimization parameters, Q being a matrix of IIR filters. For multi-block problems, the Q domain optimization method requires only a small number of optimization variables and can converge to the desired optimal value more efficiently than is the case for linear programming optimization.