Eighty nine children under 2 years of age with skull fracture were studied retrospectively--29 children with definite non-accidental injury serially recorded by the Departments of Paediatrics and Forensic Medicine, and 60 children consecutively admitted to hospital with skull fractures after accidents. There were 20 deaths including 19 among abused children. Multiple injuries and an inadequate history assisted in diagnosing abuse. Fracture characteristics found considerably more often in abused children were: multiple or complex configuration; depressed, wide, and growing fracture; involvement of more than a single cranial bone; non-parietal fracture; and associated intracranial injury including subdural haematoma. No fractures measuring more than 5.0 mm on presentation were found after accidents, but 6 of these 'growing fractures' were found in abused children. Accidents usually resulted in single, narrow, linear fractures most commonly of the parietal, with no associated intracranial injury. The results suggest that in skull fracture in young children where a minor fall is alleged, it is possible to recognise abuse by consideration of the fracture alone.