The literature on violence by psychiatric patients is reviewed. Emphasis is given to recent papers relevant to clinical management. M ost studies are cross-sectional.. The M audsley/Bethlem Violent Incidents Register is used to provide longitudinal data over a period in excess of 20 years. In acute units most violent actions are carried out by patients suffering from schizophrenia, personality disorder and alcohol or substance abuse. In longer stay units violence tends to be associated with either intractable schizophrenia or with organic syndromesÐ particularly mental impairment. Most in-patient violence is minor and repetitive. Patients at risk are usually easily identi® able by a past history of violence or aggression. Most psychiatric patients are non-violent, but a small proportion of patients account for a large number of incidents. Violence by psychotic patients is particularly likely to occur in the period leading up to and immediately following admission, when the patient is acutely disturbed. The prevention of violence is largely a matter of good psychiatric and nursing care for patients at risk. Much of the violence committed by recently admitted psychotic patients could be prevented if after care facilities were more effective in preventing non-compliance and relapse.