Identified risk factors and correlates of violence committed by patients in an acute adult psychiatric inpatient unit. Incidents of violence over a 1-yr period were retrospectively analyzed. The clinical characteristics of 49 violent patients (mean age 34.4 yrs) were compared with those of all 474) and with a sample of nonviolent patients = patients admitted to the unit (N 140). Clinical variables that predicted violent behavior were identified. = (N Results show that violence was not positively associated with schizophrenia or negatively associated with depression. Frequent medication change, high use of sedative drugs, past violent behavior, an International Classification of Diseases and Related Health Problems (ICD--10) diagnosis of dissocial personality disorder or emotionally unstable personality disorder, and long hospitalization were the most powerful predictors of violence. Compulsory (involuntary) admission, comorbid diagnoses, past self-harm, and nonalcohol drug abuse were also associated with violent behavior. It is concluded that clinicians' judgment about an inpatient's potential for violence may be augmented by knowledge of the risk factors identified in this study. Medication variables could be especially useful predictors, particularly when information about other risk factors is not available.