Purpose: The purpose of this study was to identify the prevalence of osteoarthritis and its affecting factors among a community dwelling population aged 50 and over in Korea. Methods: A total of 2,640 subjects from the 2010 Korean National Health and Nutrition Examination Survey (KNHANES) were selected. Results: The prevalence of osteoarthritis was found to be 14.3%. Multivariate logistic regression analysis shows that osteoarthritis was more prevalent as people became older; in females; in people who graduated elementary school and had never educated as compared to those who graduated college; people without home ownership as compared to those with home ownership; in people with higher waist circumferences compared to those with normal waist circumference; in people who performed moderate intensity physical activity as compared to those who did not perform those physical activity. Conclusion: Our findings highlight the prevalence of osteoarthritis and its affecting factors, promoting the screening and prevention strategies for the aged 50 and over population in Korea.