Objectives: This study identified how personal characteristics, healthy behavior and social capital might influence on physical activity of adults. Methods: This study used data from the health survey of a city of Korea. We surveyed 1,000 adults sampled by stratified sampling methods from 67,889 households. Outcome variable was the stage of physical activity which was broken into 5 categories. Sociodemographic factors, healthy behavior, self-rated health status and social capital were used as control variables. Sociodemographic factors included age, sex, educational status, economic status measured by deprivation score, residential period within survey city. Social capital was measured by Integrated Questionnaire for the Measurement of Social Capital (SC-IQ). This study used chi-square test and ordered logistic regression models to examine the associations between independent variables and physical activity. Variables were added to the regression model in three groups using a hierarchical approach. Results: Physical activity was significantly more likely to become active if they have higher educational status, healthier behavior. Among the six dimensions of SC-IQ, only "groups and networks" that is structural dimensions of social capital and "trust and solidarity" that is cognitive dimensions of social capital were significantly related to physical activity of adults. We found that a person having higher density of membership and having larger size of networks showed the high possibility of active physical activity. A person having high solidarity was significantly associated with physical activity, but general trust was inversely related to physical activity. Output dimensions of social capital did not show significant relationship to physical activity. Conclusion: We found that social capital is useful concept to explain health behaviors like physical activity. However we must consider social, cultural and political context of the study to evaluate the effect of social capital to health status and health determinants and to capture the exact meaning of relationship between them. We suggest further researches to refine the concept of social capital and to explain the relationship of social capital to diverse health determinants.