Ten cases of the right middle lobe syndromes were experienced. Nine out of ten were treated surgically, six-right middle lobectomy, one-right middle and lower lobectomy, one-right middle lobectomy and decortication, one-incidental right pneumonectomy. Pathologic diagnosis were tuberculosis in five, bronchiectasis in two, organizing pneumonia in one, and foreign body granuloma in one. There were three postoperative complications, postoperative empyema-1, pleural effusion-1, pneu-monia-1. The surgical candidates for middle lobe syndromes were; 1.Suspicious malignancy 2.Fixed bronchiectasis 3.Bronchostenosis 4.Intractability to medical treatment or recurrent atelectasis and obstructive pneumonia.