The invention relates to a method and a device for identifying a damaged bearing (4a, 4b) of a rotating shaft (1). According to the invention: the rotational speed (n) of the shaft (1) is determined; the alternating component (nAC) of the rotational speed (n) is determined, together with a smooth curve (h) of said alternating component (nAC) of the rotational speed (n); the smooth curve (h) is converted into the frequency range and a frequency response (B) of the value of the smooth curve (h) is determined. Said frequency response (B) of the value of the curve is monitored for the passing of a threshold value (G1, G2, G3, G4) and if said threshold value (G1, G2, G3, G4) is exceeded, a damaged bearing (4a, 4b) is identified. The invention thus provides a method and a device for identifying a damaged bearing (4a, 4b) of a rotating shaft (1) of a motor, which do not require a vibration sensor (11) to identify a damaged bearing (4a, 4b) of said shaft (1).