Evaluated the treatment outcome of 80 male federal inmates enrolled in a therapeutic community treatment program. Assessment focused on attrition rate, clinical improvement, motivation/effort, and institutional behaviors. Results indicate that psychopaths showed less clinical improvement, displayed lower levels of motivation, and were discharged from the program earlier than nonpsychopaths. There were significant positive treatment effects for nonpsychopaths and for a mixed group of Ss. Psychopathy Checklist scores consistently predicted treatment outcome and attrition from the program. (PsycINFO Database Record (c) 2019 APA, all rights reserved)