Between November 1985 and October 1986, attitudes and habits towards smoking were investigated among young and adult amateur athletes of the province of Pordenone, in the northeastern part of Italy. Seventy-five percent of the athletes had never smoked and 21% were current smokers. Compared with the general population, smokers were 1/3 fewer among males and 1/5 more among females; a higher number of ex-smokers was found in both sexes. The major determinants of smoking were the kind of sport in which the athletes were engaged (percentages of current smokers among athletes of endurance sports, football and other, less exhaustive, sports were respectively 3%, 23% and 20%) and having both parents who were themselves smokers. The detrimental effects of smoking on health were underestimated by the great majority of interviewed subjects. The present study supports the view that regular physical activity not only prevents youths from starting to smoke but also provides an incentive for stopping.