Introduction: The purpose of the present study was to investigate the prevalence of tobacco, hubble-bubble, alcoholic drinks, and other drugs among Karaj high-school students in 2011.Methods: The research method was a descriptive-sectional study.Participants of this study were 447 girl and boy high-school students of Karaj that were selected by clustering random sampling. For data gathering, drug abuse questionnaire, and risk and protective factors inventory were administered among selected sample.Results: According to the results, 57% of students in this study said that they have had experiences with a kind of drug including tobacco, hubble-bubble, alcoholic drinks, and other drugs at least once in their lives. The study showed the prevalence for soft drugs: hubble-bubble, tobacco, and alcoholic drinks, and for hard drugs ecstasy, opium, hashish, meth, crack, and heroin respectively.Conclusion: Soft drugs including hubble-bubble, tobacco, and alcoholic drinks, are the most common among Karaj high-school students. The prevalence of hard drugs among them is rather low.