This paper presents a reliable method for the experimental determination of high-frequency d- and q -axis inductances for surface-mounted permanent-magnet synchronous machines (SMPMSMs). Knowledge of the high-frequency d- and q-axis inductances plays an important role in the efficient design of sensorless controllers using high-frequency signal injection techniques. The proposed method employs a static locked-rotor test using an ac +dc power supply. By injecting a high-frequency rotating voltage vector into the machine, the d- and q-axis inductances may simultaneously be determined with no need to change the rotor position. Measurements are carried out at steady state. The recording of instantaneous waveforms using a dedicated data acquisition system is avoided. In this paper, experimental results are presented, on a commercial SMPMSM, using the proposed method.