A large survey was carried out by means of a self-administered questionnaire to the 30,000 teenagers attending school in a French "département" (Bas-Rhin) during spring 1976. This survey revealed some psychological factors about smoking in teenagers as they relate to school and family environment; 30.3% of the subjects were smokers. This proportion was higher in boys than in girls, and increased with age. Statistical analysis showed a greater number of smokers in non-mixed schools, in schools where adults were admitted or where regulations did not forbid smoking, as well as among boarders. We also found a greater number of smokers when the family smoked, when the parents lived outside the "départment" or belonged to the lower social classes.