A robust current control technique of a permanent magnet synchronous motor with an adaptive parameter estimation is proposed. The adaptive parameter estimation is achieved by a model reference adaptive technique where the stator resistance and the magnitude of flux linkage can be estimated simultaneously. The adaptive laws are derived by Popov's hyperstability theory and the positivity concept. The robustness of the proposed current control scheme is compared with that of the conventional scheme through computer simulation. This adaptive parameter estimation scheme can be applied to the drive systems without a shaft sensor.