Abstract: An anti-theft device for a motor vehicle includes in combination an electromagnetic wave receiver, e.g. a cellular telephone, a disabling unit which when energized by the receiver will cause the vehicle's engine to stop running and a portable electromagnetic wave transmitter, e.g., a cellular telephone, capable of emitting a signal receptive by the receiver to effect energizing of the disabling unit. In one embodiment, the disabling unit opens the electrical motor control system to stop the engine. In another embodiment, the disabling unit stops flow of fuel to the engine thereby stopping it.