A nationwide study of psychiatric in-patients driving motor vehicles and involved in accidents causing bodily injury in the years 1972--74 was undertaken. Compared with drivers in general involved in accidents causing bodily injury, drivers with a psychiatric record were characterized by an over-representation of women. A preponderance of psychiatric drivers in the age group 25--54 was observed. About 3% of drivers with a psychiatric record were involved in two or more accidents during the period studied. A greater proportion of the psychiatrically diseased group drove stolen vehicles, without valid licences, and were found not to have used safety belts at the time of the accident. Occurrence of injury was more frequent among the diseased drivers. They were more frequently alcohol intoxicated and with a higher blood alcohol level. The most commonly encountered diagnostic groups were personality disorder and transitory reactions.