Objective To ascertain firstly the proportions of smokers and ex-smokers among Irish dentists and dental students, secondly their knowledge of the role of tobacco in the aetiology of oral cancer and thirdly the attitudes of dentists to matters of public health policy relating to tobacco. Background Smoking has been associated with various diseases including oral cancer and other oral disease. Dentists are known to be potentially effective health educators and their role in smoking cessation is now appreciated. Study Design A questionnaire was distributed to dental students and a longer questionnaire to dentists; results were examined statistically. Results 14% of dentists were smokers and 45% were ex-smokers; 20% of students were smokers and 15% were ex-smokers. Most smokers declared an intention of ceasing. Almost all dentists were aware of links between smoking and oral cancer. There was strong support from dentists for higher taxes on tobacco and stricter control of advertising and sponsorship. Conclusions Irish dentists and dental students are less likely to smoke than the general public. Dentists are aware of major risk factors in oral cancer and support government intervention to reduce smoking prevalence. Such views should assist public health planners.