Abstract: A monitoring apparatus for monitoring the condition of a pressure relief rupture disk disposed in a pressure relief conduit is disclosed. The monitoring apparatus includes an electrically conductive rupture disk circuit, spaced apart electrodes affixed to the rupture disk, a rupture disk energizing circuit, a comparison circuit and an alarm circuit. The resistance between the electrodes changes when the disk ruptures. The energizing circuit includes a power source coupled to one of the electrodes. The magnitude of an output signal produced at the other of the two electrodes is dependent upon the resistance between the electrodes. The comparison circuit includes means for generating a selected magnitude output signal depending on the comparison of the magnitudes of the electrode output signal and an adjustable reference signal. The alarm circuit is electrically coupled to the comparison circuit and selectively activates an indicator alarm based on the magnitude of the comparison circuit output signal.