Central fevers are known to develop in traumatic brain injury (TBI) and are believed to be caused by injury involving the hypothalamus. Described are three patients admitted with very severe TBI secondary to motor vehicle accidents. Initial Glasgow Coma Score ratings were 3 or 4. Head computed tomography (CT) scans showed intraventricular hemorrhage in two cases and no focal injury or bleeding in the third. All patients had decorticate posturing and symptoms of autonomic dysfunction, manifested by tachycardia and profuse sweating. Each of these patients developed high fevers ranging from 38.9 degrees C to 40.6 degrees C during their hospitalization course. Centrally mediated fevers were indicated after fever workups failed to show an infectious or inflammatory source. Propranolol 20 to 30 mg every 6 hours reduced the temperatures at least 1.5 degree C within 48 hours. In each case, when weaning from propranolol was attempted, an increase in temperature to greater than 38.0 degrees C reoccurred within 3 days. Repeat workups for infectious or inflammatory causes of fever were negative. The fevers were reduced after a reinstitution of propranolol. The propranolol was continued until all signs of autonomic dysfunction abated. Central fevers after TBI have been reported to have been treated successfully with propranolol in two children with decerebrate posturing. Pharmacological, neurophysiological, and anatomic studies provide evidence of a significant central nervous system role in the regulation of blood pressure and temperature.