Out of 51 patients with traumatic intracranial haematoma admitted to a teaching hospital 11 (22%) died undiagnosed, and out of 307 such patients transferred to the West of Scotland Regional Neurosurgical Centre 111 (36%) had been deteriorating for more than 12 hours in another hospital. In two-thirds of these cases the delay was due to an erroneous diagnosis, either of cerebrovascular accident or of alcoholic intoxication.