Abstract: A mat monitor for an automatic swing door system is mountable in-line with an approach mat and a safety mat and the controller for the automatic door system. The monitor emits a visible light to indicate that a mat is properly operating without requiring that the door cycle through an opening/closing sequence. In one embodiment, a green light is illuminated to indicate that the approach mat is properly functioning and a red light is illuminated to indicate that a safety mat is properly functioning. The mat monitor is preferably mounted at the underside of the header adjacent to the controller.