A national survey was conducted to provide up-to-date data on current and ever use of tobacco among Iranian dental students. All 4th-year students of 8 randomly selected dental schools were surveyed anonymously in December 2010 using the Global Health Professions Student Survey questionnaire. Of 325 participants, 54.2% were ever users of tobacco products (73.0% of males versus 44.4% of females); 50.8% had used waterpipes, 34.2% cigarettes and 9.3% other products. The most common age at first use was 20–24 years for both sexes. Current tobacco use was reported by 20.6% of respondents, cigarette smoking by 10.8% and waterpipe smoking by 15.8%. Regression models showed that current cigarette and waterpipe smoking were significantly associated with male sex but not with type of dental school (state/private). Current waterpipe smoking was also associated with age at first experience. In view of the important role of dentists in tobacco control, the prevention of tobacco use should be stressed among Iranian dental students.