Purpose: This study was to investigate the effects of health education on health knowledge and health promoting behaviors in elementary school students. Methods: 17 sessions of health education were provided to the fifth graders in two elementary schools in Gyunggi Province and data were collected from 268 students. The data of 250 students who had responded both pretest and posttest were analyzed using SPSS program. Results: The scores of health knowledge for mental health, social health, sex and health were lower than other domain. The scores of knowledge for drug abuse/smoking and disease prevention/management were higher than other domain. Overall health knowledge was improved significantly from 0.60 at pretest to 0.81 at posttest (t=15.98, p<.001). The score of health promoting behaviors at post test was higher than score at pre test but this change was not significant (t=-0.91, p<.365). Conclusion: Health education had significant effects on health knowledge and we need to maintain and activate health education in elementary schools. Health education did not have significant effects on health promoting behaviors, we need to do further research for understanding why and how we improve health promoting behaviors.