This paper deals with model reference linear quadratic optimal control design in the frequency-domain for multiple-input-multiple-output systems. An explicit equation is given for the 1DOF (one degree-of-freedom) controller, which minimizes a given quadratic cost function. Some optimal systems are shown to be the special cases of this generalized result. For the system with minimum-phase zeros, the equivalent 2DOF (two degrees-of-freedom) control system is designed so that the loop transfer matrix can satisfy the return difference equality, i.e. the system can recover the robustness properties as in time-domain LQR optimal systems.