Objectives： This study was performed to develop a smoking prevention program for Korean high school students, and to evaluate the effects of the program. Methods： A smoking prevention program, composed of five-session curriculum, was developed by modifying several smoking prevention and cessation programs based on the Social Influence Model. The program was applied to the freshmen of a technical high school. We surveyed with a questionnaire one week before education, one week after education, and two months after education. The number of participants for data analysis were 282(181 males, 101 females). Among those, 162(97 males, 65 females) students were allocated to the education group, and the other 120(84 males, 36 females) students were allocated to the control group. The effect of education was analyzed by multiple logistic regression analysis adjusted by potential confounders. Results： Among smokers, those who had education were more likely to quit smoking (OR＝2.99, 95% confidence interval(CI) 0.84-10.64), and to decrease smoking frequency(OR＝2.29, 95% CI 0.95-5.53) in borderline significance one week after education. However, the effect of education disappeared two months after education. The effect of education was significant(OR＝9.11, 95% CI 3.22-25.76) for the increase of smoking cessation intention one week after education, and it persisted until two months after education(OR＝2.94, 95% CI 1.18-7.35). Education was also a significant predictor(OR＝1.97, 95% CI 0.89-4.37) for the increase of smoking cessation stage one week after education and it persisted(OR＝6.39, 95% CI 2.42-16.86) after two months. Among non-smokers, those who had education were more likely to decrease smoking intention one week after education(OR＝4.71, 95% CI 1.63-13.58). However, the statistical significance of education disappeared two months after education. Conclusions： The results showed that the smoking prevention program developed in this study changed smoking behaviors immdeiately after education even though the effect did not persist. However, this program was successful in increasing smoking cessation intention and stage of smoking cessation among smokers.