Background: In adolescents aged 12-14, we measured attitudes to tobacco advertising. Our purpose is to understand the relation of these attitudes to tobacco use and identify the groups most influenced by the advertising. Methods: Survey of adolescents on Gran Canaria Island, Spain, about aspects of family, school, peers, tobacco consumption, and tobacco advertising. The subjects of the double-stratified cluster sample were 1910 students at the same grade level in 33 schools; 86.6% were 13 or 14 years old, and 51.2% were boys. We generated measures for attitudes to tobacco advertising from replies to seven questions with ordinal scales by an analysis of categorical principal components. To relate attitude to tobacco advertising and the profiles of these adolescents, we used multiple regression and logistic regression models. Results: Attitudes to tobacco advertising are related to some home and school factors, but most significantly to tobacco and alcohol consumption, to amount of time at home without adults, and to peer influence. Conclusions: It is possible to draw up profiles of the students most vulnerable to tobacco advertising, and to cluster them in two groups, the "vitalists" and the "credulous." The effect of cigarette ads is different between these groups. This study can help to orientate smoking prevention. (Contains 5 tables and 3 figures.)