Introduction: Diabetes mellitus as we all know is a systemic disorder which affects many organs by causing pathological changes in them. It is considered as a leading cause of increasing morbidity and deaths in today’s world. Many studies suggested that lung is a target organ in DM and that glycaemic exposure is a strong determinant of reduced pulmonary function in DM patients theoretically morbidity, several pathological changes may affect the lungs in patients with DM.