An approach to obtain the optimal controller From an optimal criterion is presented. The controller is very general in the sense that it is multivariable, it compensates Tor process delay and it allows a penalty on the input variable variance. The controller can be obtained in two forms: the state-space model form with the steady-state Kalman filter that separates the control algorithm in distinctive steps to provide an insight into the control problem, while the transfer function form is very convenient for implementation.