We examined gender differences in manifestations of DSM-III-R antisocial personality disorder in 106 male and 34 female drug abusers enrolled in residential relapse prevention/health education treatment. In childhood, compared to males, females had more often run away but less often used weapons in fights, been cruel to animals, and set fires. Females also reported less vandalism. In adulthood, women had more often been irresponsible as parents and in financial matters, engaged in prostitution, made money finding customers for prostitutes, been physically violent against sex partners and children, failed to plan ahead, and lacked remorse. Our findings suggest that addiction treatment programs need to consider gender differences in antisocial symptomatology in the development of individualized treatment programs for both male and female clients.