Objective We assess exposure to direct-to-consumer tobacco marketing and its association with ever having tried smoking smoking within past 30 days (‘current’) and smoking ≥100 cigarettes in lifetime (‘established’) among adolescents and young adults. with ever having tried smoking current smoking and established smoking. Results Overall 12 of 15-17 year olds and 26% of 18-23 year olds were exposed to (S)-crizotinib direct-to-consumer tobacco marketing. Racial/ethnic minority non-smoking respondents were more likely to see tobacco websites than non-smoking Whites. Respondents exposed to either form of direct-to-consumer tobacco marketing were more likely to currently smoke (adjusted odds ratio[AOR]: 2.2; 95% CI 1.3-3.8) while those exposed to both forms of marketing experienced even higher odds of currently smoking (AOR: 2.7; 95% CI 1.1-6.6). We observed similar relationships for ever having tried smoking and established smoking. Conclusions Direct-to-consumer tobacco marketing reaches adolescent and young adult nonsmokers and (S)-crizotinib is associated with smoking behavior. N-myc 1 INTRODUCTION Conclusive evidence spanning decades shows that advertising and promotion activities funded by the tobacco industry cause the onset and continuation of smoking among adolescents and young adults [1]. The 1998 Master Settlement Agreement (MSA) between 46 states and the largest tobacco manufacturers established restrictions on tobacco company marketing and advertising that would be seen by youth (e.g. billboards transit ads cartoon characters major sport events) and prohibited the distribution of tobacco brand merchandise. As MSA restrictions did not encompass price discounting at the point-of-sale or direct-to-consumer marketing practices tobacco industry marketing efforts have shifted focus to these areas [2]. In 2010 2010 for example the tobacco industry spent $236 million in cigarette coupons (regularly distributed via postal mail and email) $35 (S)-crizotinib million in smokeless tobacco coupons and $22 million in internet marketing [3 4 Internet marketing may be more cost-effective to the tobacco industry than traditional advertising and provides greater reach to young smokers via social media. Passage of the Family Smoking Prevention and Tobacco Control Act granted the FDA authority to regulate marketing of tobacco products including via the (S)-crizotinib mail and internet [5] – marketing modalities to which adolescents and young adults may be especially vulnerable [6 7 Compared to established adult smokers adolescents and young adults may be particularly sensitive to price discounting for tobacco products [8-10] and therefore more receptive to the direct-to-consumer marketing that offers these discounts. In addition to price discounting some adolescents may also actively seek direct-to-consumer marketing because of their strong need for novel experiences and risky behaviors. Of course direct-to-consumer tobacco marketing may not be originally intended for adolescent and young adults. Nonetheless these vulnerable populations may be exposed to such marketing because their parents older siblings and older friends that smoke. We do not know the extent to which adolescents and young adults especially nonusers of tobacco are exposed to direct-to-consumer tobacco marketing. We also do not know whether exposure to direct-to-consumer marketing is associated with tobacco use over and above well-established correlates of smoking including sensation seeking friends smoking and parental smoking. In this paper we seek to fill important evidence gaps in our knowledge of adolescent and young adult exposure to direct-to-consumer tobacco marketing by addressing the following three research objectives. First we assess the level of exposure to direct-to-consumer tobacco marketing via (S)-crizotinib the mail and the internet among adolescents and young adults. Second we determine the characteristics of nonsmoking adolescents and young adults associated with increased exposure to direct-to-consumer tobacco marketing. Finally we assess whether the level of exposure to direct-to-consumer tobacco marketing is associated with smoking behavior among adolescents and young adults. 2 METHODS Recruitment We recruited participants through a three-stage sample selection process. In stage 1 we identified a list-assisted sample of 578 542 landline.