Purpose: This study focused on identifying health promotion behavior of older adults, and factors affecting this behavior. Method: The participants in this survey analysis were Koreans aged 65 or over who had the ability to communicate and could do cognitive thinking, and who consented to participate in the survey. The survey questionnaire included items on demographic characteristics, level of depression, social support, activities of daily living, self-efficacy, and health promotion behavior. Data were analyzed using the SPSS Windows 14.0 program. Results: There were significant differences in health promotion behavior according to religion, economy and health status. Levels of depression, social support and self-efficacy had strong correlations with health promotion behavior. The factors that had the greatest effect on health promotion behavior were social support and self-efficacy. Conclusion: As social support and self-efficacy have been found to affect health promotion behavior in older adults, programs developed to enhance health of older adults should include activities to enhance both social support and self-efficacy.