BACKGROUND To know the smoking habits of the Spanish teachers, the anti-smoking teaching and the influence on the smoking habits of the students. METHODS A cross-sectional study was conducted using a self-administrated and anonymous questionnaire. Of the he questionnaires addressed to the headmasters of 8,000 school centers selected as a random sample among the 18,457 existing in Spain, 3,050 valid answers were received. RESULTS 29.7% of Spanish teachers are smokers, smoking significantly more (p < 0.001; 95% C.I.) in Secondary education (37.2 +/- 15.9%) than in Primary education (26.2 +/- 19.4%) and 7% smoke in front of the pupils, significantly more in state schools (p < 0.05) and in Secondary education (p < 0.001). There are positive correlations between the percentage of smoking teachers and the percentage of pupils who tasted tobacco (p < 0.001) or are regular smokers (p < 0.001), and also between the percentage of teachers who smoke in front of the pupils and the percentage of students who tried tobacco (p < 0.001) or smoke regularly (p < 0.001). In the school centers which apply the non-smoking regulation or teach antitobacco contents, the percentage of teachers smoking in front of pupils is significantly lower (p < 0.001). CONCLUSIONS The attitude of teachers has an influence on the students; headmasters must ask for the application of non-smoking regulation and include health education contents in school curriculum.