The American Legacy Foundation's national EX® campaign, which ran on radio and television in 2008, was designed to promote smoking cessation among adult smokers. The incremental societal cost of EX, in 2009 dollars, was $166 million. Data from eight designated media market areas studied indicate that in a hypothetical nationwide cohort of 2,012,000 adult smokers ages 18-49, EX resulted in 52,979 additional quit attempts and 4,238 additional quits and saved 4,450 quality-adjusted life-years. Incremental cost-utility estimates comparing EX to the status quo-that is, the situation that would have existed in the eight markets with no campaign and no change in cessation behavior-ranged from a cost of $37,355 to $81,301 per quality-adjusted life-year, which suggests that the campaign was cost-effective. These findings bolster previous evidence that national mass media campaigns for smoking cessation can lower smoking prevalence in a cost-effective manner, among both adults and young adults ages 18-24 who are smokers. M ass media campaigns can be used effectively to reduce youth smoking prevalence and promote adult smoking cessation, particularly when combined with other tobacco control efforts.