Introduction: Chronic Obstructive Pulmonary Disease (COPD) is a common, preventable and treatable disease, that is characterized by persistent respiratory symptoms and airflow limitation that is due to airway and/or alveolar abnormalities usually caused by significant exposure to gases or noxious particles. Over the past decade, RDW has been associated with incipient myocardial infarction and heart failure in the general population has emerged as the one of the strongest predictor of poor survival in patients with established heart failure and coronary artery disease.12 RDW has also been proposed as marker of immune activation correlating with levels of tumour necrosis factor alpha and interleukin-6.The process of inflammation and dysregulated hematopoiesis may be linked, since interleukin6 is important for production of hepcidin in liver and thus may indirectly regulate iron metabolism.13,14 Hence this study was conducted to observe Red Blood Cell Distribution Width in Patients with chronic obstructive pulmonary disease.