An Automatic Rodent Detector and Repellent system keeps the rodent away from the protected areas like data rooms, server rooms, telecommunication rooms and UPS rooms and even in hotels, large warehouses, food industry and hospitals. It works on the principle of high-frequency ultrasonic sounds that are generated by the transducers. This causes them discomfort and to panic and they leave the area sooner or later. The noise produced by the automatic rodent detector and repellent system in inaudible to the human ears and guard the area against rodent problems. The area in which the system works depends on its size, structure, partitions and content.