Records of 116 violent incidents perpetrated by special care patients over a twelve-month period were retrospectively examined. There was a marked seasonal variation in the number of incidents. Incidents took place predominantly in the seclusion rooms and in communal areas having relatively high patient density. Patients admitted from the National Health Service following unmanageable violent behaviour were over-represented. A small number of patients were responsible for a high proportion of incidents. Implications for prevention are discussed.