Introduction: Diabetes mellitus is a group of metabolic diseases characterized by persistent hyperglycemia having rising prevalence and incidence in all parts of the world. In view of its micro-vascular complications, it affects all major organs of the body viz. heart, kidney, eyes etc. Its complications in lungs were less known and less understood. There is increasing evidence in literature about diabetes affecting lungs. Our study designed to study the effects of diabetes on lungs. Objectives: To evaluate and compare the pattern of pulmonary dysfunction amongst diabetics and non– diabetics. To assess the effect of HBA1c levels and duration of diabetes on pulmonary dysfunction. Methods: Subjects with diabetes (after applying exclusion criteria) were posted for pulmonary function testing. For control group, people for wellness centre were selected who are non-diabetic. Results:There was statically significant difference in PFT parameters between diabetes and control group. Poor glycemic control (rising HbA1c) showed significant changes in FVC, FEV1 with duration of disease. Conclusion: Amongst diabetics, pulmonary dysfunction represents in the form of restrictive abnormality i.e. decrease in FEV1, FVC and increased or normal FEV1/FVC ratio. Our study supports to the theory of pulmonary fibrosis as one of the complications of diabetes.