Objective: To build up a new microcontroller thermoelectric system to achieve renal hypothermia.Material and methods: Renal hypothermia system was tested under in vivo conditions in the kidneys of tenMongrel dogs. Ambient temperature was evaluated using two different microcontrollers. In order to ensurehypothermia in the renal parenchyma, selection can be made among 4 modules and sensors which detectthe temperature of the area. The temperature range of the system was adjusted between -50°C and +50°C.Results: When single and double poles of the kidney were cooled, initial mean intraperitoneal temperaturevalues were found 37.7°C for rectum and 36.5°C for renal cortex and medulla. After the temperature of thecooling module was set to 12°C, the module was placed on the poles of the kidney. After fifteen minutes,temperature was 15.4°C in the lower pole of the kidney, 28.1°C in the cortex of the other side and 29.2°C inthe intramedullary region. The temperature was found to be 15°C in the vicinity and 26.1°C in the cortexacross the module. After the system was stabilized, a very slight change was observed in the temperature.Conclusion: Hypothermia system developed ensured desired cooling of the targeted part of the kidney;however, it did not cause a change in the temperature of other parts of the kidney or general body temperature.Thus, it was possible to create a long-term study area for renal parenchymal surgery