Purpose: This study aimed to determine whether the severity of chronic obstructive pulmonary disease (COPD) affects recurrence-free survival in non-small-cell lung cancer (NSCLC) patients after surgical resection. Patients and methods: A retrospective study was performed on 421 consecutive patients who had undergone lobectomy for NSCLC from January 2008 to June 2011. Classification of COPD severity was based on guidelines of the Global Initiative for Chronic Obstructive Lung Disease (GOLD). Characteristics among the three subgroups were compared and recurrence-free survivals were analyzed. Results: A total of 172 patients were diagnosed with COPD (124 as GOLD-1, 46 as GOLD-2, and two as GOLD-3). The frequencies of recurrence were significantly higher in patients with higher COPD grades (P<0.001). Recurrence-free survival at 5 years was 78.1%, 70.4%, and 46.4% in non-COPD, mild COPD, and moderate/severe COPD groups, respectively (P<0.001). By univariate analysis, the age, sex, smoking history, COPD severity, tumor size, histology, and pathological stage were associated with recurrence-free survival. Multivariate analysis showed that older age, male, moderate/severe COPD, and advanced stage were independent risk factors associated with recurrence-free survival. Conclusion: NSCLC patients with COPD are at high risk for postoperative recurrence, and moderate/severe COPD is an independent unfavorable prognostic factor.