This is a descriptive study of 50 randomly selected male patients retained in a maximum-security state hospital for mentally disordered offenders. Data regarding the prevalence of several indicators of potential organic brain dysfunction are presented, including: (1) a diagnosis of any organic brain disorder, (2) a history of severe head injury with loss of consciousness, (3) a history of seizure activity, (4) evidence of cognitive impairment, (5) abnormal neurological findings, and (6) other relevant neurodiagnostic or historical findings. Results show that multiple indicators of potential brain dysfunction were present in 64% of the cases. At least one indicator of potential brain dysfunction was present for 84% of the subjects. Subjects with a diagnosis or history suggesting brain dysfunction were significantly more likely to have been indicted for violent criminal charges (p = 0.01). Implications of these findings for clinical treatment and forensic science decision-making are discussed.