Background The goal of this study was to assess the effects of Minnesota's comprehensive, statewide smokefree law on young adults' perceived opportunities to smoke in restaurants and bars. Purpose Differential effects of the law were examined for those living with and without previous local smokefree ordinances. Methods Telephone surveys were conducted 612 months prior, 06 months prior, and 06 months after Minnesota's statewide smokefree law went into effect. Participants included young adults from a population-based cohort in Minnesota (n=1446) and from four other Upper Midwest states that serve as a comparison (n=238). Results A greater proportion of Minnesota participants (regardless of previous law) reported it was very hard for an adult to find a place to smoke in both restaurants and bars/clubs after the statewide law, compared to the comparison group. Effects were greater among Minnesota participants who did not live with a local smokefree ordinance previously. Conclusions Within 6 months of Minnesota's statewide smokefree law, Minnesota young adults, even those who lived with a prior local smoking ordinance, believed it was more difficult for adults to find a place to smoke in restaurants and bars/clubs. Changing perceived opportunities to smoke in the state may be an initial step in changing social norms and smoking behaviors. These results suggest that statewide smokefree laws may provide additional barriers to smoking, beyond those obtained through local ordinances.