Abstract: The sensor and alarm system for monitoring a relative position of a prosthetic device with respect to the residual portion of an amputee's limb includes a battery power supply; a proximity sensor for generating a position signal indicative of the relative position of the prosthetic device and the residual portion in the prosthetic device near the residual portion, and an alarm device for signaling when the prosthetic device is located in an injurious position or positions.