In this study, we aimed to investigate the frequency of postoperative hypothermia in our hospital.In Keçiören Training and Research Hospital, 165 ASA I-III patients between the ages of 18 and 81, whose operation times were longer than 30 minutes were included in this study. In addition to recording the demographic data of the patients, the body temperatures were also measured twice in the preoperative preparation room, and in the postoperative care unit in the forehead with infrared thermometers. The operation types, the durations, the anesthesia types, and the patients heating status in the perioperative period were recorded. If the body temperature was 35oC or below, it was accepted as hypothermia; and if it was 34oC and below, it was accepted as deep hypothermia. We compared the data of normothermic, hypothermic and deep hypothermic patients. 79 women (47.9%) and 86 men (52.1%), totally 165 patients were included in this study. It was detected that 7 patients (4.2%) were heated preoperatively. It was determined that 16 patients (9.7%) were hypothermic in the postoperative period, and 3 of them were deep hypothermic. There were no statistically meaningful differences between the hypothermic and non-hypothermic patients in terms of age, gender, ASA, type of anesthesia, and operation time (p>0.05). Although postoperative hypothermia has not been found as a common problem in our operating theaters, we observed that most of the postoperative hypothermia cases were in percutaneous urological operations. In order to reduce the frequency of postoperative hypothermia, specific precautions for this type of operations should be taken.