Background: COPD has reported as a risk factor of lung cancer. However, there is limited data whether COPD can be a predictor of mortality in lung cancer. This study was performed to investigate that COPD can affect the mortality of the patiens with lung cancer. Methods: Patients who were diagnosed with lung cancer during Jan 2007 to Dec 2008 at Chonnam University Hawsun Hospital were analyzed retrospectively. We collected data gender, age, BMI, smoking history, TNM stage, treatment method, spirometry result and identified the state of death. Hazard ratio of mortality in lung cancer patients were calculated for each variables including COPD stage by Cox proportional hazards regression. Results: The variables significantly associated with mortality of patients with lung cancer were gender, age, BMI, smoking history, TNM stage, treatment method, COPD stage by GOLD in univariated analysis. In multivariated analysis, age, BMI, TNM stage, treatment method, and GOLD stage were the significant predictors of mortality in lung cancer. In the univariated analysis, the hazard ratio for normal stage was 1.24 (95% CI 0.92-1.65) in stage 1, 1.65 (95% CI 1.25-2.18) in stage 2, 2.33(95% CI 1.62-3.34) in stage 3. In the multivariated analysis, the hazard ratio for normal stage was 1.10 (95% CI 0.78-1.56) in stage 1, 1.33 (95% CI 0.96-1.85), in stage 2, 1.59 (95% CI 1.04-2.44) in stage 3. Conclusion: This study suggests that COPD is one of the significant factors that predict mortality of lung cancer. COPD should be noted for the reduction of mortality of lung cancer.