Abstract: An elevator door monitoring system determines if any hatch door at any floor along an elevator shaft or any other door leading to the shaft is opened while an elevator cab is away from the door. The system includes a plurality of non-contact hatch door monitors, such as infrared proximity detectors. At least one monitor is positioned on the elevator shaft at a respective location generally opposite each hatch door along the shaft. Each monitor detects the opening of the respective hatch door without direct contact therewith, e.g., by directing radiation toward the door and measuring the distance to the door. If the distance is too great, indicating that the door is open and no elevator is present, the monitor produces an alarm signal. The alarm signal is sent to a control circuit which takes the elevator out of service and operates audible and visual alarms in response thereto.