History and Objectives: Postoperative shivering is a common complication in patients under anesthesia and because of the importance of its etiology and the controversies on the relationship between core body temperature and shivering, this study was carried out on referrals of Sina hospital in Tehran in 1997.

Materials and Methods: Case-control strategy of this study was performed on 60 patients divided into shivering and non-shivering groups. Postoperative tremor with tonic pattern and having a 4 to 8 cycle/min waxing-and-waning component was considered as shivering. Core body temperature was estimated by a nasopharyngeal probe in both groups and they were compared using t-test. The means were reported as Mean±SD.

Results: This research was carried out on 90 patients, i.e., 30 patients for case group (Shivering) and 30 patients for control group (Non-shivering). Both groups were similar regarding age, gender and temperature of operation room. Core body temperature in non-shivering group was 36.11±0.33 and in shivering group was 35.32±0.61 (P<0.001). Meanwhile, prevalence of shivering was 36.7 percent.

Conclusion: There exists a relationship between core body temperature and the occurrence of shivering. Therefore, it is recommended to perform more studies in this field regarding shivering and its complications.