Our aim was to rate the severity of injuries to hands by powered wood splitters. The patients were identified from a computerised registry, and the cause of injury was confirmed by written questionnaire and structured telephone interview. Information about the anatomy of the injury was gathered from patients' records and radiographs. Severity of injury was rated according to the Hand Injury Severity Scoring System (HISS system) and the Injury Severity Score (ISS). The reliability of HISS rating was tested. The mean Hand Injury Severity Score (HISS) was 63 and the mean ISS was 3.7. Twenty-five (19%) of patients had minor, 41 (31%) had moderate, 30 (23%) had severe, and 35 (27 %) had major injuries when scored by the HISS system. Children's injuries were more severe than those of adults. There was no difference in severity between injuries made by wedge and screw splitters. It is not possible to avoid serious hand injuries from powered wood splitters completely by prohibiting one of the two main types of splitter.