Hookah tobacco smoking (HTS) has been increasing, particularly among young adults and has similar health effects compared to cigarette smoking. The link between HTS and poly-tobacco use is well documented, but fewer show an association between HTS and alcohol use. It is essential to identify factors that increase the risk for or addictiveness and consequences of HTS, given its growing prevalence. This study examined whether the association between HTS and poly-tobacco use differed as a function of age and alcohol consumption within in a sample of 1223 adult cigarette smokers. Approximately 20% of participants reported HTS. Compared to non-users, hookah users were more likely to be male, highly educated, and to report drug and alcohol use, binge drinking, and poly-tobacco use but were less likely to be heavy smokers (>= 10 cigarettes per day). Regression analyses predicting number of tobacco products used (excluding cigarettes and HTS) indicated a three-way interaction of HTS, frequency of alcohol use, and age such that the association between HIS and number of tobacco products used was strongest for younger respondents who consumed alcohol more frequently. As observed in previous studies, alcohol is an important risk factor in the relationship between HTS and poly-tobacco use, particularly among younger cigarette smokers. The links between alcohol, HTS, and poly-tobacco use should be considered when developing HTS education and prevention materials directed toward younger cigarette smokers. Findings provide information relevant to FDA's interest in the addiction potential of HTS and its link to poly-tobacco use. (C) 2017 Elsevier Ltd. All rights reserved.