Pulmonary gangrene is a rare complication of severe pulmonary infection in which a pulmonary segment or lobe is sloughed. It is a part of a spectrum of disease in which lung tissue is devitalized(such as necrotizing pneumonia, pulmonary abscess), but apart from them, pulmonary gangrene has more extensive area of necrosis and thrombosis of large vessels plays a prominent role in the pathogenesis. We experienced a case of pulmonary gangrene in 71 year old female obstructive pneumonia patient with non-small cell lung carcinoma. She complained high fever, chill and despite treatment with antibiotics, pneumonia progressed to empyema. At that time chest radiograph showed a large cavity including sloughed lung tissue, freely moving to dependent position at both lateral decubitus view. RML and RLL were resected and compression of pulmonary vessels by enlarged lymph nodes was observed. Defervescence was obtained immediate postoperative period and the patient was discharged after infection control with antibiotics, chest tube drainage. The perivascular lymph nodes dissected during lobectomy were proved to be reactive hyperplasias. We speculated that the carcinoma caused obstructive pneumonia, in turn, resulted in reactive hyperplasia of the draining lymph nodes surrounding the large vessels and finally the lung tissues supplied by them necrotized and sloughed.