Psychopathic criminals commit more crimes, are more prone to recidivism, and more likely to engage in violent crimes and other aggressive behavior than nonpsychopathic criminals. Less is known about forensic patients, both with and without psychopathy, and their aggression. In the current study, patients in a maximum security hospital were examined with respect to their psychopathy and its predictive value on institutional management and dangerousness. In this regard, the Psychopathy Checklist (PCL) and the Psychopathy Checklist - Revised (PCL-R) have proven to be valid and reliable measures of psychopathy. The present study was an attempt to establish predictive validity for a new version: the Psychopathy Checklist Screening Version (PCLSV). As such, this study examined the PCL-SV's relationship to (a) diagnoses of Antisocial Personality Disorder according to DSM-III-R criteria and (b) the Personality Assessment Inventory (PAI) Aggression, Drug Problems, and Antisocial Features scales. The influence of major Axis I disorders on the assessment of psychopathy with the PCLSV was also examined. Participants were 150 male forensic psychiatric patients at Vernon State Hospital who were committed for various reasons: incompetence to stand trial, initial evaluation and treatment after having been found not guilty by reason of insanity, and manifest dangerousness. Chart reviews were completed for a six month follow-up period during which all instances of aggressive or socially disruptive behaviors were recorded. Results supported the predictive validity of the PCL-SV as a measure of psychopathy for aggression and treatment noncompliance. Unexpected findings among correlations of the PCL-SV with the PAI Antisocial Features scale were examined and discussed. A review of the costs and benefits of the PCL-SV in clinical decision making is presented and the clinical utility of the present findings is discussed.