A 49-year-old woman visited our clinic on July 12th, 2006, complaining of discomfort in fingers of both hands, edema of both lower limbs, and pain in the right shoulder and chest. Chest X-ray examination showed an infiltrative shadow with pleural effusion and loss of lung volume in the left lower lung field. She was treated with CTRX, but it was ineffective, and she was therefore admitted to Kurume University Hospital on July 21st, 2006. Chest CT demonstrated pyothorax and loss of lung volume in the left lung. Culture of a sample obtained by thoracentesis yielded Nocardia asteroides. The pulmonary nocardiosis improved after oral administration of trimethoprim-sulfamethoxazole, and the patient was discharged on August 25th 2006. No immunological impairment was observed, and the serum levels of ACHT and cortisol were normal. In February 2007, however, she developed facial acne, facial edema ("moon" face), centripetal obesity, and weight gain. Cushing syndrome was diagnosed on the basis of tests including a low-dose dexamethasone suppression test. To the best of our knowledge, there has been no previous report of pulmonary nocardiosis with pyothorax in a patient with Cushing syndrome. We assume that the present patient had pre-(sub-) clinical Cushing syndrome when she presented with pulmonary nocardiosis and pyothorax.