Tobacco is one of the major causes of premature deaths in the world, and any effort to improve the cost-effectiveness of smoking cessation is worth while. The costs and effects in years of life saved (YLS) were estimated for a tobacco 'Quit and Win' (Q&W) contest in Sweden. The contest was conducted during the autumn of 1988 and included two strategies: a national mass media strategy and an organizational strategy for Stockholm County. A total of 12,840 people participated in the Q&W contest. The model for analysis included programme effects and programme costs, and the data was presented in (YLS). Both effects and costs were discounted. Data about non-smoking participants after 12 months and the number of spontaneous quitters was based on random samples of participants and of the general population, respectively. The programme costs included intervention as well as evaluation costs, e.g. costs of personnel, campaign materials, distribution, prizes for the contest, rent and administration and overhead costs for the project group and the collaborating organizations. The cost per YLS varied between US$188 and US$1222. The Q&W contest, as a method of helping tobacco users quit, compares favourably with most preventive and treatment programmes, and the method seems to be quite an effective way for society to use scarce resources.