Frome nine dental clinics within the Public Dental Service in the City of Göteborg, 2145 patients aged 14 to 19 answered a questionnaire concerning their tobacco habits. Tobacco was used in some form by 27 per cent of the patients and use increased with age. Smoking was more common among girls than among boys: 24 and 12 per cent, respectively. The statistical analyses showed that smoking as a habit and an increased number of cigarettes smoked per day are positively correlated with increases in the number of decayed, missing and filled teeth and the number of initially decayed proximal surfaces. Further, all caries epidemiological data were significantly higher among patients with tobacco habits compared to non-users. It can be concluded that there is a correlation between the tobacco habit and increased caries prevalence. However, dietary and oral habits have to be further elucidated before any definite conclusions can be made regarding the effect of the tobacco habit per se on the development of caries.