Method for monitoring the safety of a transport system, which transport system comprises a transport appliance as well as a synchronous motor for moving the transport appliance and in which method: - the motion information of the transport appliance is determined from a signal of a motion sensor of the transport appliance, and - the motion information of the transport appliance is determined from electrical parameters of the synchronous motor, namely its source voltage and/or variation in its inductance, and - the motion information of the transport appliance is further determined from the signal of a motion sensor of the synchronous motor, characterized in that the motion information of the transport appliance determined from the signal of the motion sensor of the synchronous motor is compared with the motion information of the transport appliance determined from the signal of the motion sensor of the transport appliance, and if the motion information of the transport appliance determined from the signal of the motion sensor of the synchronous motor deviates from the motion information of the transport appliance determined from the signal of the motion sensor of the transport appliance by more than a set limit value, - the aforementioned motion informations of the transport appliance determined from the signal of the motion sensor of the synchronous motor and from the signal of the motion sensor of the transport appliance are compared to the motion information of the transport appliance determined from the electrical parameters of the synchronous motor, and - on the basis of the comparison the operating condition of the aforementioned motion sensors (4, 6) is determined, - while if the motion information of the transport appliance determined from the signal of the motion sensor of the transport appliance deviates from the motion information of the transport appliance determined from said electrical parameters of the synchronous motor by more than a set limit value, an emergency stop is executed. - the motion information of the transport appliance is determined from a signal of a motion sensor of the transport appliance, and - the motion information of the transport appliance is determined from electrical parameters of the synchronous motor, namely its source voltage and/or variation in its inductance, and - the motion information of the transport appliance is further determined from the signal of a motion sensor of the synchronous motor, characterized in that the motion information of the transport appliance determined from the signal of the motion sensor of the synchronous motor is compared with the motion information of the transport appliance determined from the signal of the motion sensor of the transport appliance, and if the motion information of the transport appliance determined from the signal of the motion sensor of the synchronous motor deviates from the motion information of the transport appliance determined from the signal of the motion sensor of the transport appliance by more than a set limit value, - the aforementioned motion informations of the transport appliance determined from the signal of the motion sensor of the synchronous motor and from the signal of the motion sensor of the transport appliance are compared to the motion information of the transport appliance determined from the electrical parameters of the synchronous motor, and - on the basis of the comparison the operating condition of the aforementioned motion sensors (4, 6) is determined, - while if the motion information of the transport appliance determined from the signal of the motion sensor of the transport appliance deviates from the motion information of the transport appliance determined from said electrical parameters of the synchronous motor by more than a set limit value, an emergency stop is executed.