We assessed the effect of the interrelationship of mothers' and fathers' tobacco and marijuana use with their personality attributes on some of their child rearing behaviors. We used a longitudinal design to analyze the data of 258 males and females who were seen four times over a 13-year period from early adolescence through young adult parenthood. Thirty-one percent of the multiple regression analyses revealed significant interactions between the effect of tobacco or marijuana use and a personality attribute on child rearing. The majority of these significant interactions suggested that protective personality characteristics were offset by substance use risks resulting in less adequate child rearing. If these results are substantiated in an experimental intervention, it suggests that having resilient personality attributes does not protect against the negative effects of tobacco or marijuana use on child rearing.