The authors have analyzed retrospectively a series of 288 consecutive patients with severe head injury observed between January, 1977, and May, 1980. Seventy-three patients were excluded as not being compatible with those of the International Data Bank. The remaining 215 patients complied with the definition of coma given by Jennett. All patients, after appropriate cardiopulmonary resuscitation, diagnostic measures, and, when required, surgical treatment, were managed in the Neurosurgical Intensive Care Unit with endotracheal intubation, controlled hyperventilation, mild dehydration, dexamethasone in standard doses, and sedation. The mortality rate was 39.5%. Of the survivors, 59.2% made a good recovery, 18.4% remained moderately disabled, 6.1% were severely disabled, and 1.5% were in a persistent vegetative state. The most reliable predictive criteria were: absence of brain-stem reflexes, neurological status, abnormal motor patterns, arterial hypotension, and presence of mass lesions. It is concluded that no sign has an absolute prognostic value when considered independently of its time course.