A neutron monitor was designed with the unique feature of continuously self-auditing circuits. The monitor has four simultaneously operable channels; each alarms at a preset neutron level. Neutrons are detected by polyethylene-moderated BF3 tubes connected to the monitor by coaxial cables as long as 100 ft. Detector preamplifiers are not necessary and the detectors are unaffected by gamma fields up to 500 R/h.