Background: Several studies have reported an increase in risk behaviors among adolescents after experience of parental divorce. The aim of the study was to investigate whether parental divorce is associated with risk behavior among adolescents independent of mental health problems, first when early divorce was experienced, and second after experience of late parental divorce. Method: One prospective (n=1861) and one cross-sectional study (n=2422) were conducted using data from two Young-HUBRO surveys in Oslo, Norway. All 15/16 year-old 10th grade students who participated in the first survey in the school year 2000/01 were followed-up in 2004 when they were 18/19 year-olds. The follow-up rate was 68%. The prospective study investigated the influence of late parental divorce that occurred between the age of 15/16 and 18/19. In the cross-sectional study we focused on early parental divorce that occurred before the participants were 15/16 year-old. Results:In the prospective study we could not discern a significant association between experiencing late parental divorce and an increase in risk behaviors among 18/19 year-old adolescents. In the cross-sectional study parental divorce was significantly associated with cigarette smoking and using doping agents. Conclusion: Parental divorce that occurs when the children of divorced parents are 15/16 year-old or younger is associated with an increase in cigarette smoking and use of doping agents. However, no evidence of significant association is found between experience of late parental divorce and risk behaviors in late adolescence.