Chronic obstructive pulmonary disease (COPD) is a very common disorder caused primarily by cigarette smoking. Recently national and international guidelines were produced in order to standardize the management of the disease. It became apparent that only a few items in these documents are based on evidence-based studies. Diagnosis should be made in relation to the definitions, symptoms, signs and routine investigation. Spirometry is essential for the diagnosis of COPD. The two well documented modes of treatment, namely cessation of smoking and long-term oxygen therapy are discussed in detail.