Purpose: This study examined the effectiveness of an adolescent school -based smoking prevention program. Methods: The study was done with a nonequivalent control group pretest-posttest design. The subjects of the present study were 399 non-smoking high school students in Kyongbuk province. The subjects were divided into 184 experimental group members in G city who participated in a school-based smoking prevention program and 216 control group members in K city who did not participate. Data were collected from June to November 2011. collected data were analyzed using SPSS/WIN 18.0 through $x^2$-test, independent t-test and ANCOVA. Results: The experimental group had significantly increased knowledge of smoking, knowledge of smoking prevention program, attitude of smoking, skill of smoking prevention in comparison to the control group. Conclusion: The school-based smoking prevention program delivered to non-smoking adolescents is an effective method of encouraging smoking prevention and can be utilized as an effective nursing intervention for non-smoking adolescents.