THE STUDY WAS UNDERTAKEN TO CONTRIBUTE TO THE RESEARCH LITERATURE ON PERSONALITY DIFFERENCES AND ON CHANGES IN PATTERNS OF EMOTIONAL DISTURBANCE ASSOCIATED WITH AGE, AS WELL AS TO MAKE A NEW CONTRIBUTION TO THIS AREA OF STUDY BY EXAMINING PERSONALITY DIFFERENCES AMONG LAW OFFENDERS AT VARIOUS AGES. CLINICALLY DERIVED IMPRESSIONS SUGGEST THAT OLDER LAW OFFENDERS SHOW PATTERNS OF 'PSYCHIATRIC' RATHER THAN 'SOCIOPATHIC' DISTURBANCES WHICH DISTINGUISH THEM FROM YOUNGER OFFENDERS, THEREBY HAVING IMPLICATIONS FOR DIFFERENT METHODS OF TREATMENT BY THE CRIMINAL JUSTICE SYSTEM. THE SAMPLE, CONSISTING OF 362 ADULT MALE OFFENDERS, WAS DIVIDED INTO 6 AGE GROUPS (18-19; 20-29; 30-39; 40-49; 50-59; 60-85), AND AVERAGE MINNESOTA MULTIPHASIC PERSONALITY INVENTORY (MMPI) PROFILES WERE CONSTRUCTED FOR EACH GROUP. THE ASSESSMENT WAS PART OF THE POSTCONVICTION, PRESENTENCING DISPOSITIONAL EVALUATION. THE STATISTICAL ANALYSES INVOLVED TESTS COMPARING EACH AGE GROUP WITH EVERY OTHER ON THE MMPI VALIDITY AND CLINICAL SCALES. IN ADDITION, THE GROUPS WERE COMPARED ON THE THREE GOLDBERG (1972) INDICES: NEUROTIC VERSUS PSYCHOTIC, SOCIOPATHIC VERSUS PSYCHIATRIC, AND NORMAL VERSUS DIVIANT. THE FINDINGS SHOW THAT THE GREATER THE AGE DIFFERENCES BETWEEN GROUPS, THE LARGER THE PERSONALITY DIFFERENCES ON VARIOUS MMPI SCALES AND INDICES. THERE WERE SLIGHT INCREASES ON 'NEUROTIC' SCALES ASSOCIATED WITH AGE, LARGER DECREASES ON 'PSYCHOTIC' SCALES WITH AGE, AND AN ABRUPT DECREASE IN THE OLDEST GROUP ON A SCALE ASSESSING IMPULSIVENESS AND ACTING-OUT TENDENCIES. THE RESULTS CONFIRM THE VIEW THAT OLDER OFFENDERS ARE IN GREATER NEED OF 'NONCRIMINAL' TREATMENT OR REHABILITATION PROGRAMS THAN OFFENDERS IN GENERAL. (AUTHOR ABSTRACT MODIFIED--DJM)