摘要:Background: Students, clergymen and teachers as role models can be very important in encouragement or prevention of cigarette smoking in young people. The aim of this study was to compare prevalence of smoking in 3 male groups of teachers, clergymen and university students. Also, study their knowledge and attitude towards it and the prediction of their future consumption. Methods: In a cross sectional study in 2009 in Tehran, Iran, 1,271 male students, 549 clergymen and 551 teachers were randomly enrolled. Each participant completed the global adult tobacco survey questionnaire. Knowledge, attitude and prediction of smoking for the next 5 years were questioned in these 3 groups. Chi-squared test and logistic regression were used for analysis. P < 0.05 was considered significant. Results: Prevalence of cigarette smoking was 31.1%, 21.9% and 27.2% among students, clergymen and teachers, respectively. Smoking in students was not associated with poor knowledge but were in teachers and clergymen. The odds ratio of smoking in students, clergymen and teachers was higher among those with having inappropriate attitude towards it (OR = 1.6, 6.1 and 4.5). Those with poor knowledge had an inappropriate attitude and predicted higher chance of cigarette consumption in the next 5 years ( P < 0.0001). Inappropriate attitude in all 3 groups resulted in higher prediction of future smoking ( P = 0.008). Conclusions: This study revealed that the prevalence of smoking among male students and teachers was higher than general population and clergymen who equally smoked. Also, level of knowledge and attitude of students were lower than teachers and clergymen.