BACKGROUND. In 1985, The Minnesota Legislature initiated a long-term and broad-based program to deter adolescent tobacco use. The initiative was funded by higher taxes on tobacco products and combined school-based programming, mass-media campaigns, and local community grants. The Minnesota-Wisconsin Adolescent Tobacco-Use Research Project was designed to evaluate this effort by monitoring adolescent tobacco use and related factors in Minnesota and Wisconsin from 1986 to 1990. The results presented in this paper indicate that the Minnesota initiative dramatically increased Minnesota schoolchildren's reported exposure to the anti-smoking messages in the mass media but had little effect on smoking-related beliefs or smoking behaviors. CONCLUSIONS. These results, together with the findings from other recent studies, suggest that even dramatic increases in exposure to anti-tobacco messages in the mass-media, in the absence of a substantial and sustained school-based tobacco prevention measures, may be insufficient to generate reductions in adolescent tobacco use.