(57) An out of proximity alarm system useful for indicating when the distance between two bodies has increased beyond a predetermined distance is disclosed. In the preferred embodiment, the system comprises a radio transmitter attachable to one of the bodies, such as a personal article such as a briefcase and having a pulsed R.F. output. A radio receiver carried by a second body, such as a person, receives the transmitted signal when the two bodies are within range of each other. The receiver incorporates a time delay stage which is kept disabled by the received pulsed signal. Should the distance between the two bodies increase beyond a predetermined amount the pulsed signal will have insufficient strength to keep the time delay stage disabled, thus activating an alarm and alerting the carrier of the receiver that he has left the personal article behind.