Background and objectives: There is a debate regarding the level of vitamin D and its impact on lung function in patients with COPD. We evaluated the relationship of vitamin D with lung function and quality of life (QOL) in persons with obstructive airway disease (OAD) in Korea. Methods: The present study was based on the Korean National Health and Nutrition Examination Survey 2010-2014. The plasma level of vitamin D (25-hydroxyvitmain D) was measured by radioimmunoassay. The EuroQol-5D (EQ-5D) index was used to assess the QOL. OAD was defined as less than 0.7 of FEV1/FVC and more than 40 years old. Results: The study population comprised of 1,475 persons with OAD and 9,406 healthy persons. OAD itself was not risk factor for vitamin deficiency after adjustment for sex, age, smoking, and BMI. Vitamin D was correlated with FEV1 pred. % (FEV1%) and FEV1 (p=0.014 and p=0.000, respectively) in persons with OAD. Vitamin D was risk factor for decrease of FEV1% and FEV1 after adjustment for sex, age, smoking, and BMI in persons with OAD. Vitamin D deficiency group (lower than 20 ng/mL) showed lower FEV1 than did non-deficiency group (p=0.005) in persons with OAD. However, vitamin D did not affect any factors of EQ-5D after adjustment of sex, age, BMI, and smoking in persons with OAD. Conclusion: Vitamin D related with decrease of lung function, but not QOL in persons with OAD.