Using a standardized schedule of questions, this study examined (a) the prevalence of self-report of violent thoughts by patients hospitalized for mental disorders compared with nonpatients, (b) the persistence of violent thoughts after discharge, and (c) the relation between patients' violent thoughts while hospitalized and violent acts within 20 weeks after hospital discharge. About 1/3 of the patients reported thoughts of violence while hospitalized, more than twice the proportion found among nonpatients. Reporting violent thoughts in hospital was significantly related to engaging in violent acts within 20 weeks after discharge for non-White patients, patients without major mental disorder but with substance abuse diagnoses, patients with high symptom severity, and patients whose reports of violent thoughts persisted after discharge. Reporting violent thoughts was significantly related to measures of psychopathy, anger, and impulsiveness.