Several studies in adults demonstrated a positive relationship between the number of cigarettes smoked and the urinary cotinine. The aim of this work was to analyze the passive and active smoking exposure of 333 sixteen-year-old students, demonstrated by their urinary cotinine, in comparison with the smoking habits of all the cohabitants. This last information was obtained from a questionnaire and urinary cotinine in mothers. The second purpose of this work was to observe whether the smoking habits of parents can promote the voluntary active exposure to tobacco smoke in children. The considered students represent a particular group of people (16 years old) having a life-style still strictly bound to the smoking habit of parents. In fact, the nonactive smokers show urinary cotinine levels described by the following means: 28.81, 39.35, 39.62, and 57.67 ng/mL. This finding demonstrates a trend of exposure from no exposure to a maximum level of passive exposure. Similar results can be observed by considering the urinary cotinine of mothers. Finally, the active smoking habit potentially acquired by the adolescents seems to be induced also by emulation of the smoking habits of fathers. This possibility is demonstrated by a light positive and statistically significative correlation with the number of cigarettes actively smoked and, consequently, with urinary cotinine.