Abstract: An improved vehicle security system is disclosed in which different modes of arming and disarming the system are utilized. The system uses an arming feature to disable operation of the vehicle which is initiated by the vehicle ignition switch being turned off following which one or more doors of the vehicle are opened. The system also uses a voice actuated alarm deactivation procedure in which operation of the vehicle is enabled following voice identification of a spoken password as belonging to an authorized individual. The vehicle security system uses a positive interlock in which both the vehicle's starting system and its ignition system are disabled when the system is armed.