The scope of this paper is to develop a methodology for a time invariant, single rate, approach to optimal multirate regulator design. The proposed method is developed employing a time invariant expanded discrete time model for the multirate system capable of providing all the information between sampling instants needed to compute the corresponding control weighting matrices for each base rate interval and then to accumulate all the control effort at the last base rate sampling interval for which all sampling switches are synchronized. In this way, the design of an optimal multirate regulator reduces to an equivalent single rate design of the same dimensionality as the original sampled system