We herein present a case in which an emergency operation was performed for an intrathoracic hemorrhage resulting from a scapular prolapse after a thoracotomy, a rare complication of this procedure. A 59-year-old man had undergone a right upper lobectomy with an extended resection of the posterior chest wall including the second to fourth ribs due to a direct invasion by a lung cancer. On postoperative day 80, we performed an emergency operation as the patient had gone into shock due to an intrathoracic hemorrhage with a right scapular prolapse. The scapula protruded through the enlarged fourth intercostal space. The prolapsed scapula was reduced and the defect in the chest wall was covered with Marlex mesh.