Postoperative fever is a usual source of concern among caregivers and patients' family given that it may reflect a wide range of complications. The objective of this paper was to outline the expected postoperative temperature variation after hemispherectomies, and to establish factors that affect this curve. From 1987 to 2003, 30 patients were hemispherectomized in our institution. Among them, 24 patients without clinical diagnosis of infection were selected for this study. Postoperative axillary temperature from each patient was recorded over 10 days. Data was initially analyzed for all 24 patients and, later, for subgroups by (1) surgical technique (functional hemispherectomy, anatomical hemispherectomy, and hemispherotomy) and (2) hemispheric volume of the causative pathology (groups with large, moderately atrophic, and severely atrophic hemispheres). There was a trend of temperature elevation (p=0.06) over the first 4 days in all patients where 14 subjects recorded values over 38.5 degrees C, and 3 over 39.0 degrees C. Temperature curves from subgroups undergoing different techniques presented no statistical differences. However, the group including causative pathologies with larger hemispheres had a higher temperature curve when compared to patients with severely atrophic hemispheres (p<0.05). Our findings support the view that fever is an predictable event after hemispherectomies and causative pathologies with larger hemispheres present higher postoperative temperatures.