Adolescents exposed chronically to tobaccotobacco smoke have been found to have reduced pulmonary function as well as an increased risk of lung cancer and a serious heart disease. Consequently, reducing exposure to tobacco smoke is an important public health goal. This study was conducted to develope the exact evaluation method of student smoker or heavy exposure from ETS, and the change on smoking behavior and attitude after a stop-smoking program. From the study, we concluded that the cotinine concentrations in saliva from students indicate exactly whether they are smoker or not. Also, it was found that the more and exact informations from both the cotinine analysis and the questionnaire were obtained than from only the questionnaires. The non-smokers had more positive effects on the changes of cog-nitions, behaviors and attitude about passive-smoking after a stop-smoking program than the smokers. The results of this study show that through both the accurate determination of cotinine in saliva and the questionnaires, the smoking status and the tobacco education effectiveness can be predicted.