The participants included 55 males. Thirteen youths aged 16-18 years came from a young offenders’ open-custody facility, 13 students ages 16-18 from a local secondary school and with no prior arrests or convictions, 15 adult offenders ages 20-40 incarcerated at a local jail, and 14 adults ages 20-30 years from a local university and without prior arrests or convictions. Participants completed tests that included the Qualitative Score of the Porteus Maze, Paragraph Completion Method, Wisconsin Card Sorting Tests, Minnesota Multiphasic Personality Inventory, Coopersmith Self-Esteem Inventory, Buss Durkee Hostility Inventory, and Carlson Psychological Survey. Additional instruments included the Michigan Alcohol Screening Test, Drug Abuse Screening Test, Test of Non-verbal Intelligence Form A, and two scales of the Wechsler Adult Intelligence Scale Revised. Results of stepwise linear discriminant function analyses revealed significant differences between offenders and non-offenders in executive functioning and personality, regardless of age. Offenders had significant impairment in social competency, judgment, foresight, and perspective taking. They also had higher levels of impulsivity, immaturity, and aggression than did non-offenders. Tables and 60 references