This study was conducted to assess the levels of 25 OH vitamin D in patients of COPD, to check the correlation between vitamin D levels and FEV1/FVC ratio and to know the association of vitamin D levels and the staging of COPD as per GOLD guidelines. Sixty patients of COPD and fifty–five healthy age matched control were included. Serum 25 hydroxy vitamin D was measured. Levels < 10ng/ml was considered as deficient and 10–30ng/ml as insufficient. More number of COPD patients had Vitamin D deficiency and insufficiency. Patients with lower levels of vitamin D had lower FEV1, lower FEV1/FVC ratio, higher smoking index and a higher Gold staging of 3–4. There was no significant correlation between BMI and Vitamin D. Patients of COPD are at risk of vitamin D deficiency and insufficiency with a significant association between smoking index and lung function. Vitamin D levels should be checked in all patients of COPD.