In order to study smoking habits of children and adolescents from Sousse in Tunisia, we undertook an epidemiological survey on a representative sample of 1569 pupils aged between 13 and 19 years with a global answer rate of 95,4%. The objective of the study was both to describe Tunisian adolescent smoking behaviour and also to evaluate the influence of the home environment, friends and the different socio-demographic factors on acquiring or maintaining the habit. Students were surveyed in schools using a self-administered, anonymous questionnaire. Overall 7,6% of our sample smoked tobacco with prevalence amongst boys being much higher than in girls: 14,7% versus 1,1%; X(2)=103,4, p=0,00001. The smoking prevalence rose with age: in boys it increased from 3,4% at 13 years to 32,3% at 19 years; X(2)=40,9, p=0,0001. 60,6% of youngsters interrogated were exposed to passive smoking at home. Peer smoking behaviour has a clear effect on the tobacco habits of boys. These findings suggest school and medical authorities should design specific programs to limit the spread of the tobacco phenomenon in youngsters.