Purpose: This study was conducted to measure the relationships between ecological factors and Navy personnel` s physical activity (PA) based on McLeroy`s Ecological model. Methods: A cross-sectional survey was conducted with a convenience sample of 184 Navy personnel working in 10 Navyships. A self-reporting questionnaire consisted of measures of intrapersonal, interpersonal, organizational and community factors related to Navy personnel` s PA. Data were analyzed by descriptive statistics, x2-test, t-test, analysis of variance, and hierarchical multiple regression using SPSS/WIN 17.0 programs. Results: Their mean PA level was 2,848.1±3,344.5 MET- min/week, and mostly moderate level (50.5%). Hierarchical multiple regression analysis showed that religion, working department, working type, perceived health status and community environment were significant PA correlates. Conclusion: Community environmental factors as well as intrapersonal factors were significantly associated with Navy personnel`s PA, indicating that community health nurses should expand an approach for individual- level behavioral change to incorporate Navy personnel specific community environmental barriers into PA interventions.