The invention relates to a method for detecting a rotating stall fault in a compressor (12) which is driven by means of a three-phase current motor (8) fed by an inverter. According to the invention, an instantaneous estimated value (^m) which is calculated from measured power converter output currents (iS1, iS2, iS3) and a measured rotational-speed-proportional signal (ω) is compared with an instantaneous setpoint value (m*) determined from a measured rotational-speed-proportional signal (ω) and a predetermined rotational-speed-proportional signal (ω*), in such a way that in the case of inequality a signal (SRS) is generated which indicates that the rotating stall fault has occurred. In this way, it is possible for the rotating stall fault to be detected without pressure sensors and/or oscillation pickups in a compressor (12) which is driven with a three-phase current motor (8) fed by inverter.