OBJECTIVES: Measuring the prevalence and determinants of narghile smoking among teenagers in schools in the southern suburbs (Dahia) of Beirut, Lebanon. METHODS: A simplified questionnaire was self-completed by intermediate and secondary students selected from private and public schools in Dahia the year 2001-2002. Variables obtained included details on narghile and cigarette smoking, socio-demographic characteristics of the student and his/her family, friendship networks, and beliefs regarding health. RESULTS: A total of 1461 students completed the questionnaire, of which 24% admitted regularly (> once/week) smoking the narghile and 14.4% occasionally, with a male predominance. The initiation was at about 13.6 yrs of age, but it varied from as low as 5 to 18 yrs. At least 28% of first narghile trial took place with a member of the immediate family, even though 58.2% initiated with a user friend. The monthly cost of using narghile did not exceed 7 USD for about half of narghile users in that areCONCLUSIONS: Narghile use is a behavior gaining in importance in Lebanon in general, and in the Dahia area in particular. Its initiation among adolescents means that the probability of addiction is higher and the adverse health consequences are potentially more severe. It requires immediate interventional procedures including the launching of a campaign of national awareness for which hard data, such as those provided by this study, will be needed.