Background: Although smoking is the most important and modifiable cause of chronic obstructive pulmonary disease (COPD), other risk factors including tuberculosis (TB) and asthma are also associated. Clinically, it is not uncommon for COPD patients to have several risk factors more than one. The aim of this study was to determine the prevalence of airflow limitation (FEV1/FVC＜0.7) according to the risk factors, and to investigate the impact and interaction of them on airflow limitation. Methods: From Korean National Health and Nutrition Examination Survey (KNHANES) between 2008 and 2012, we analyzed participants over 40 year-old with spirometry, chest X-ray (CXR) and questionnaire concerning asthma and smoking history. Results: Of 12,631 participants, 1,548 (12.3%) had airflow limitation. The prevalence of airflow limitation in smokers (＞10 pack-year), asthmatics, and those with inactive TB were 23.9%, 32.1%, and 33.6%. The prevalence increased with the number of risk factors; 86.1% had airflow limitation if they had all these three risk factors. Impacts of inactive TB and asthma on airflow limitation were equivalent to 47 and 69 pack-year history of smoking, respectively. Airflow limitation resulted from much less amount of smoking in those with inactive TB and asthma. Smoking and inactive TB had a potential interaction on development of airflow limitation with marginal significance (p=0.054). Conclusions: Asthma and inactive tuberculous lesions increase susceptibility to smoking in the development of airflow limitation. People with these risk factors should be seen as a major target population for anti-smoking campaigns to prevent COPD.