Observers rated patients on a measure of the interpersonal circle (Chart of Interpersonal Reactions in Closed Living Environments), from which scores on dominance-submission and nurturance-hostility dimensions were derived. The study hypothesized that criminality is associated with the hostile- dominant quadrant of the interpersonal circle; criminality is conceptualized as a general disposition to violate legal rules, a disposition that varies among individuals. The study found that mentally ill offenders were more submissive than those without mental illness, but in both groups, offenders with higher numbers of criminal convictions were more dominant than those with fewer convictions. Correlational analysis showed that offenders with extensive criminal careers who were not mentally ill had a more dominant and coercive interpersonal style. Similar but less pronounced trends were apparent among mentally ill offenders. These findings suggest that persistent lawbreaking may involve attempts to master a social environment perceived as hostile. Illness-related factors probably account for the greater submissiveness of offenders who are mentally ill. Disentangling illness-related factors from stable personality traits is problematic in this group. Treatment of mental disorder may reduce the risk of further antisocial behavior among persons who begin criminal behavior later in life, but it may have little impact on mentally ill offenders who manifested criminal behavior early in life. 4 tables and 39 references