Respiratory disease is an increasingly significant contributor to morbidity and mortality. Lung cancer and chronic bronchitis continue to be major clinical problems. As the population lives longer, there are many older patients with pulmonary disease. These elderly patients are increasingly likely to undergo both emergency and elective surgeries, with the associated risks of pulmonary embolism and postoperative infection. This chapter summarizes the main uses of nuclear medicine in respiratory diseases including pulmonary embolism, sarcoidosis and other inflammatory diseases, tumors, and obstructive airway disease and alveolar–capillary membrane permeability assessment.