Background and objective: The association between airflow limitation severity and post-operative pulmonary complications (PPCs) among COPD patients undergoing extra-pulmonary surgery is unknown. We evaluated the association between forced expiratory volume in 1 s (FEV 1 ) and PPC in COPD patients undergoing extra-pulmonary surgery. Methods: Using prospective cohort of PPC evaluation for extra-pulmonary surgery, we identified 694 COPD patients who conducted PPC evaluation before extrapulmonary surgery between March 2014 and January 2015 at a tertiary hospital, Seoul, Korea. Results: The overall incidence of PPC was 24.4%. The incidence of PPC in quintiles 1-5 of FEV 1 (% predicted) was 31.4, 25.8, 23.7, 21.6 and 19.7%, respectively (P for trend: 0.019). In fully adjusted multivariable models, the relative risks (RRs, 95% CI) for PPC comparing participants in quintiles 1-4 of FEV 1 (% predicted) with those in quintile 5 were 1.69 (1.03-2.79), 1.41 (0.83-2.37), 1.26 (0.75-2.11) and 1.30 (0.76-2.22), respectively (P for trend: 0.046). The association of severe airflow limitation with respiratory failure and post-operative exacerbations was stronger in participants who did not use bronchodilators compared with those who did. Conclusion: We found a progressive and significant relationship between severity of airflow limitation and the incidence of PPC in COPD patients undergoing extra-pulmonary surgery. Furthermore, perioperative bronchodilator use was associated with a reduced risk