Background: The prevalence of chronic cough and sputum production consistently increased with increasing airflow limitation. And chronic sputum has long been recognized as a consequence of tobacco smoking. In comparison, prevalence of chronic phlegm varied from 3.1 to 31 percent in other studies. However, there is no report about the prevalence and risk factors of chronic sputum in Korea. This study was planned to estimate the prevalence of chronic phlegm and to study its associated factors among the general Korean population. Methods: A cross-sectional survey was planned in the general population of Korea. This survey collected information on National Health and Nutrition Examination Survey 2010. Results: A total of 2801 subjects aged 40 years and higher were enrolled in the study with 1263 males and 1538 females. The prevalence of chronic phlegm was 5.5 per cent (8.0:3.4 %, M:F). A significant association was observed between chronic phlegm and age, gender, and current smoking. A multivariate analysis confirmed independent association of age and current smoking for chronic phlegm (p＜0.05). Conclusions: The prevalence of chronic phlegm was 5.5 per cent and in the general population. Smoking was an important preventable risk factor identified in this study and efforts towards smoking cessation are crucial to achieve good respiratory health in the community.