Population-based, longitudinal study that enrolled 3636 youth from Minnesota and 605 youth from comparison states age 12 to 16 years in 2000-2001. Participants were surveyed by telephone semi-annually about their tobacco-related attitudes and behaviors. Goals were to evaluate the effects of the Minnesota Youth Tobacco Prevention Initiative and its shutdown on youth smoking patterns, and to better define the patterns of development of tobacco use in adolescents. A multilevel sample was constructed representing individuals, local jurisdictions and the entire state, and data were collected to characterize each of these levels. Major topics covered by the survey are cigarette use, nicotine dependence, alcohol use and dependence, cigarette access, quitting smoking, use of other tobacco products and marijuana, parent smoking habits, tobacco marketing, emotions and stress perceptions, and perceptions and opinions of smoke-free laws, tobacco companies, and tobacco age restrictions. Demographic information includes age, education, ethnicity, gender, marital status, and income level.