Objectives. This prospective study examined the effect of tobacco marketing on progression to established smoking. Methods. Massachusetts adolescents (n = 529) who at baseline had smoked no more than 1 cigarette were reinterviewed by telephone in 1997. Analyses examined the effect of receptivity to tobacco marketing at baseline on progression to established smoking, controlling for significant covariates. Results. Adolescents who, at baseline, owned a tobacco promotional item and named a brand whose advertisements attracted their attention were more than twice as likely to become established smokers (odds ratio = 2.70) than adolescents who did neither. Conclusions. Participation in tobacco marketing often precedes, and is likely to facilitate, progression to established smoking. Hence, restrictions on tobacco marketing and promotion could reduce addiction to tobacco. (Am J Public Health. 2000;90:407-411) Reprinted by permission of the publisher.