The authors describe a one-year prospective study carried out in Créteil from October, 1983 to October, 1984 in 155 selected patients admitted for at least 24 hours with traumatic head injury. Patients with gunshot wounds of the head were excluded from the study. 30% of the patients were infants, 60% were adults aged between 15 and 60, and 5% were over 60; 48% were not comatose (initial Glasgow symptomatic score [GSC] greater than or equal to 8) and 36% were free of any neurological symptom. Prognosis was related to the initial neurological status, to the patient's age and to underlying diseases, such as alcoholism. 10 out of 11 patients with an initial GSC of 4 or less died, against 12 out of 144 with a GSC above 5. At the first CT scan, 10% were found to have an extradural haematoma, but the examination was normal in 20% of patients with neurological symptoms and/or coma; 22% of the CT scans were abnormal without any clinical symptom, as was the case, in particular, with 4 extradural haematomas. Surgery was performed in 24% of all patients and in 17.4% of infants, whereas the percentage reached 30% in alcoholic patients, due to the frequency of intracerebral haematomas in this population. In 16% of the 155 cases, barbiturates were used to treat uncontrolled intracranial pressure higher than 20 mmHg. 15% of the 155 patients deteriorated; a second operation was necessary in 9 cases. The final outcome on discharge was: 112/155 patients with good recovery or moderate disability, 22 with severe disability, 5 with persistent vegetative state and 21 deaths.