SummaryA questionnaire on smoking behaviour was sent to a randomized sample of Belgian Physicians in 1983. The replies showed that 32% were smokers, 33% ex-smokers and 35% non-smokers. Smoking was less prevalent among the younger physicians (P<0.05). Rather surprisingly 26% of the smokers presented a«consonant»behaviour, i.e. they declared that they did not want to stop smoking and that they had never tried to do so. Consonant smokers agreed, however, that smoking is harmful, and, therefore, have adopted less harmful smoking habits: they inhale less, smoke smaller amounts and smoke more cigars and pipes and less cigarettes than the 47% dissonant smokers i.e. those who declare that they would like to stop smoking and have already tried to do so.