THE MMPI HAS BEEN A STANDARD TEST INSTRUMENT FOR CORRECTIONAL SETTINGS. THE PURPOSE OF THIS STUDY, CONDUCTED AMONG 36 INMATES AT THE MAXIMUM SECURITY U.S. PENITENTIARY IN MARION, ILL., WAS TO TEST THE UTILITY OF THREE MMPI SCALES IN DISCRIMINATING BETWEEN INMATES WHO WERE MANAGEMENT PROBLEMS AND THOSE WHO WERE NOT. THE PD (PSYCHOPATHIC DEVIATE) SCALE INCLUDES 50 ITEMS REFERRING TO FAMILY, OCCUPATION, ADDICTIVE HABITS, SEX, AND STEALING. THE MA (HYPOMANIA) SCALE HAS 45 ITEMS THAT SUGGEST IMPULSIVE BEHAVIOR OR LACK OF INHIBITORY DRIVE. THE HY (HYSTERIA) SCALE CONSISTS OF 60 ITEMS AND FOCUSES ON SUCH PSYCHOSOMATIC COMPLAINTS AS VAGUE HEADACHES, DISTURBED SLEEP, HEART PAINS, AND INABILITY TO MAKE QUICK DECISIONS. SOME ITEMS REFER TO CRIME, SEX, LIE TELLING, AND THE PROJECTION OF FAULTS. FROM INSTITUTIONAL FILES, 18 GENERAL POPULATION INMATE MMPI SCORES WERE MATCHED FOR AGE, RACE, AND CRIME CONVICTION TO THOSE OF 18 INMATES WHO HAD A HISTORY OF SEVERELY DISRUPTIVE PRISON BEHAVIOR. ONE WAY ANALYSES OF VARIANCE INDICATED THAT ONLY THE HY SCALE DISCRIMINATED BETWEEN PROBLEM AND NONPROBLEM INMATES. CONTRARY TO EXPECTATIONS, PD AND MA SCORES WERE NOT SIGNIFICANTLY DIFFERENT IN BOTH GROUPS; BOTH GROUPS HAD HIGH PD AND MA SCORES. THE DATA PROVIDE STRONG EVIDENCE THAT HY SCALE SCORES CAN ACCURATELY DISCRIMINATE BETWEEN INMATES WHO CREATE PROBLEMS AND THOSE WHO DO NOT. THE ARTICLE INCLUDES A 13-ENTRY BIBLIOGRAPHY AND A GRAPH OF THE STATISTICAL RESULTS OF THE STUDY. (SAJ)