A theft protection for an electronic device, in particular an optionally portable computer, a mobile telephone or a PDA, includes an electrical cable (2) with a coupling connector (3) for coupling to a corresponding coupling connector of the device. Alarm elements are connected to the cable (2) which are able and adapted to generate an alarm signal in the case the device is stolen. The alarm elements (4) are accommodated in a housing (1) separate from the device. The housing is provided with fastening elements (5) for a mechanical connection of the housing to a fixed object (9). The alarm elements include detection elements which are adapted and able to detect an interruption of the electrical cable connection (2), in addition to signalling elements (4) which generate the alarm signal when the interruption is detected.