Chronic obstructive pulmonary disease (COPD) is a progressive disease characterized by restrained airflow via airways predominantly in expiration. COPD is a serious disease that can cause in many cases repeated incapacity for work, early invalidity and even death. The pathogenesis of COPD is poorly understood and many details about the natural history are missing . Currently accepted concepts include a progressive inflamatory response, possibly associated with unrestrained proteolytic enzyme release and toxic oxygen radicle production, induced by cigarette smoke and other inhaled pollutants. Obviously susceptible smokers have an accelerated rate of deterioration of expiratory airflow compared with other persons and smoking cessation restores the rate of decline to normal. Symptomatic patients or those with chest x-ray abnormalities resulting from COPD generally have moderately severe or advanced disease. Thus the typical symptoms and signs of COPD occur late in its evolution. Patients with early COPD are often asymptomatic or nearly so and diagnosis can be made only by documenting the presence of expiratory airflow obstruction. Simple spirometry is all that is required and it should be available in the doctor`s office for screening all cigarette smokers and other persons at risk for COPD.