Social network theory and analysis are applied to examine whether adolescents who fill various social positions that characterize peer group structure differ in prevalence of current smoking. One thousand and ninety-two (1,092) ninth graders in one school system named their three best friends, allowing the identification of each adolescent as clique member, clique liaison, or isolate. At four of five schools, the odds of being a current smoker were significantly higher for isolates than for clique members and liaisons. The relationship was not explained by demographic variables or by the number of friends who smoke.