Chronic obstructive pulmonary disease affects more than 26 million adults in the United States. Family physicians provide care for most of these patients. Cigarette smoking is the leading risk factor for chronic obstructive pulmonary disease, although other risk factors, including occupational and environmental exposures, account for up to one in six cases. Patients presenting with chronic cough, increased sputum production, or progressive dyspnea should be evaluated for the disease. Asthma is the disease most often confused with chronic obstructive pulmonary disease. The diagnosis of chronic obstructive pulmonary disease is based on clinical suspicion and spirometry confirmation. A forced expiratory volume in one second/forced vital capacity ratio that is less than 70 percent, and that is incompletely reversible with the administration of an inhaled bronchodilator, suggests chronic obstructive pulmonary disease. Disease severity is classified by symptomatology and spirometry. Joint guidelines from the American Thoracic Society and the European Respiratory Society recommend a single quantitative test for alpha1-antitrypsin deficiency in patients diagnosed with chronic obstructive pulmonary disease who remain symptomatic despite bronchodilator therapy. Other advanced testing is usually not necessary.