An improved electromagnetic clutch is provided with a permanent magnetic return mechanism. The clutch includes a rotor connected to a driven device, such as a refrigerant compressor, a flywheel connected to a driving device such as an internal combustion engine, and a contact plate assembly for transmitting torque between the flywheel and the rotor when moved from a disengagement to an engagement position by an electromagnet. Permanent magnet assemblies are used to bias the contact plate assembly into a non-engagement position when the electromagnet is deactuated. The use of permanent magnets in lieu of resilient mechanical components such as springs to bias the contact plate assembly into a return position substantially extends the service life of the clutch when it is used in conjunction with a prime mover such as a diesel engine, whose output is accompanied by momentary spikes of high torque.