This study was designed to investigate the impact of family and peer role models during the early adolescent years on smoking onset and on subsequent daily smoking among young adults. Baseline data were collected from a sample of 827 students and their parents in 1979. Participating students were recruited among 5th, 6th and 7th graders (11-14 years old) attending six schools in Oslo, Norway. The same students were invited to participate in a 2-year follow-up survey in 1981 and in a 10-year follow-up survey in 1989 when their average age was 23.4 years. Both at baseline and in 1981, smoking (experimental or regular) was strongly associated with smoking behaviour of friends and siblings. Parental smoking and parents' educational level were not significant predictors of their offspring's smoking in 1979. While friends' smoking in 1979 or 1981 remained a significant bivariate predictor of daily smoking in 1989, mother's baseline smoking emerged, in multivariate analysis, as the most important long-term predictor of daily smoking among young adults. These results point to the importance of including parents in smoking prevention efforts targeting adolescents.