Postoperative pulmonary complications still occur with significant frequency, causing 13%-25% of all postoperative deaths. The likelihood of pulmonary complications is greater following abdominal procedures and prolonged periods of anesthesia and sedation, but is seemingly unrelated to the type of anesthesia employed or the route of administration. An acute respiratory infection is a contraindication to surgery except under the most emergent conditions. Detection of the presence of chronic bronchopulmonary disease may be difficult but usually is possible if the symptoms of cough, sputum, and breathlessness are sought and evaluated. In patients who demonstrate clinically some pulmonary abnormality, the use of simple pulmonary function tests is quite helpful in evaluating both the physiologic nature and the severity of the disease.