Rupture of aneurysm of descending thoracic aorta into the right thoracic cavity is an uncommon manifestation and, therefore, carries a high mortality rate. Sixty seven-year-old female was referred to our hospital due to ruptured aneurysm of descending thoracic aorta into the right thoracic cavity. Emergency operation was performed to replace the ruptured descending thoracic aorta through a left thoracotomy and to remove huge hematoma in the right thoracic cavity through a right thoracotomy. Post-operative chest radiograph showed well-expanded right lung which appears to prevent a serious respiratory complication. The patient recovered uneventfully after seven days of respiratory support.