Background:Airway blockage that is either irreversible or somewhat reversible is a hallmark of chronic obstructive pulmonary disease (COPD), a condition that develops progressively. The present study evaluated utility of quantitative CT parameters in assessment of COPD patients.Materials & Methods:85 confirmed cases of COPD of both genders were selected. Following the American Thoracic Society's (ATS) recommendations, a pulmonary function test was conducted. All underwent a 64-slice CT scan in a craniocaudal orientation while being breath-held from the lateral costophrenic sulci to the lung apices.Results:There were 25 non- smokers, 47 mild smokers and 13 moderately heavy smokers. The difference was significant (P< 0.05). There was significant difference in the means of all the three parameters between the individual groups with different smoking exposure (P< 0.05). All the parameters showed an inverse relationship with the FEV1. LAA% showed the best correlation with FEV1 (r- -0.56). WA% and pi10 also showed statistically significant correlation with r values of −0.42 and −0.72, respectively. Among individual groups, statistically significant correlation was obtained between FEV1 with LAA% and pi10 in the never-smokers. Correlation with WA% wasnot significant in this group.LAA% showed higher specificity and sensitivity than WA% and Pi10.Conclusion:FEV1 and dyspnea in patients with chronic obstructive lung disease are influenced by QCT markers of airway illness.