Objectives : This study is to examine the effectiveness in the oral health promotion through the oral health education for high school students. In adolescence, there seems to be the high incidences of dental caries, gingivitis and periodontal diseases. Concerning preventing all such outbreaks, this study focuses on applying the oral health education to their health education, and on analyzing its effectiveness. Methods : To verify its effectiveness, this research administered 85 students of both genders of a certain high school in Seoul during May-October 2010, followed by the evaluation of DMFT, S-PHP, and CPITN. Results : First, the oral health promotion through the education was statistically significant in the permanent effects of index (FT index). Second, the effect of S-PHP index gradually decreased in statistics from the first to the fifth session, but, after five months ever since the education, it seemed relatively higher in the next sessions. Third, the changing in the level of CPITN decreased continuously as the students received the education repeatedly, but there is no significant difference in statistics for each session. Conclusions : For the oral health promotion in the high school students, the education ought to be focused on the behavior-change objectives rather than on the knowledge-based objectives. The repeated education for tooth-brushing instruction should be stressed for preventing from returning to the old bad behaviors.