Although many studies report on the parent/child bond and its negative correlation with substance use, few researchers have examined the interaction between the parent/child relationship and parent substance use to predict adolescent use. In this study, 763 adolescents, 11-15 years old, along with their parents and siblings, participated in a seven-year longitudinal study of family influence on adolescent substance use. In the study's initial years, 34 percent of the participants withdrew. The findings emphasized the importance of the interaction between parent use and the parent/adolescent relationship. A good parent/adolescent relationship did not always protect the child from substance use. If the parent, particularly the mother, had a good relationship with the adolescent and that parent used substances, the child was more likely to use drugs. Likewise, female adolescents were more likely to imitate paternal use and non-use of a substance if they had a good, rather than a poor, relationship with their father. Additionally, parental abstinence did not always ensure abstinence in the child. An adolescent with a poor relationship with a non-using parent was as likely to use substances as a using parent in a poor parent/adolescent relationship. (RJM)