: This work proposes a systematic methodology for the optimal selection of controller parameters, in the sense of minimizing a performance index which is a quadratic function of the tracking error and the control effort. The performance index is calculated explicitly as an algebraic function of the controller parameters by solving a Zubov-type partial differential equation. Standard nonlinear programming techniques are then employed for the calculation of the optimal values of the controller parameters. The solution of the partial differential equation is also used to estimate the closed-loop stability region for the chosen values of the controller parameters. The proposed approach is illustrated in a chemical reactor control problem. Copyright