A maximum efficiency control of Synchronous Reluctance Motor (SynRM) using a novel on-line stator resistance estimator is presented. The proposed stator estimator entails utilizing the nature that stator resistance variation affects the accuracy of stator-flux-estimation-based inductance estimation values, but does not affect the selection of stator current vector in the maximum efficiency control system of SynRM. The proposed maximum efficiency control is implemented on a 1.1kW flux barrier type SynRM having cross-magnetic saturation effect. To correctly estimate the stator resistance and to improve the performance of the maximum efficiency control system in low speed are discussed with experimental verifications.