Purpose: The purpose of this study was to examine physical activities and health belief in order to provide basic data on obesity prevention and management among elementary school students based on the health belief model. Methods: Participants included 194 fifth grade students in an elementary school located in Seoul. Data were collected by questionnaires and physical measurement, including weight and height. The SPSS Win 17.0 program using descriptive statistics, ANOVA with Scheffe post hoc tests, and Cronbach`s alpha coefficients was used in data analysis. Results: Significant differences were observed in physical activity according to perceived severity (F=3.444, p=.034), perceived benefit (F=7.674, p=.001), perceived barrier (F=21.014, p<.001), and self-efficacy (F=22.098, p<.001). A significant difference in physical activity (t=4.502, p<.001) and perceived severity (t=-2.278, p=.024) was observed according to gender. Significant differences in physical activity (t=7.633, p=.006), perceived barrier (t=10.826, p=.001), and self-efficacy (t=5.928, p=.016) were observed according to obesity status. Significant differences were observed in physical activity (F=7.503, p=.001), perceived susceptibility (F=37.904, p<.001), and perceived barrier (F=3.425, p=.035) depending on level of satisfaction with body image. Conclusions: In order to promote physical activity among children with low physical activity, development of program with an emphasis on the benefits of physical activity and physical activity self-efficacy, and to decrease the barriers to physical activity is needed.