Most studies addressing the importance of the family environment on children's emotional development and psychological treatment associate the characteristics of the mother's personality with the child's pathology, disregarding the characteristics of the father's personality. Therefore, this study's objective was to investigate the personality characteristics of fathers of children with antisocial tendencies by means of the psychodiagnosis interventive method and to investigate the potential relationship of such characteristics to the treatment results obtained for children. Six fathers of seven children were evaluated by the Rorschach test. Follow-up of the cases indicated five therapeutic successes and two failures. The paternal personality characteristics associated with success included the absence of severe impairment in the test of reality, control of impulses, and interpersonal relationships, in addition to a neurotic organization of personality. The results show the importance of including information concerning the father's personality when prescribing therapies and establishing prognoses.