Neurogenic tumors are common in posterior mediastinal tumors. In most cases, tumors were accidentally showed on simple chest X-ray. In some cases, they were presented by symptoms which were induced by nerve compression or airway compression. But as in our case, neurogenic tumor with spontaneous hemothorax is very rare. A 45-year-old man admitted to emergency room of other hospital because of acute right chest pain and dyspnea. A chest X-ray showed a right pleural effusion. Hemothorax was diagnosed after closed thoracostomy. Following chest CT showed posterior mediastinal mass. The patient was transferred to our hospital. T spine MRI showed dumbbell shaped mass. Diagostic impression was neurogenic tumor. The pathologic result was neurilemmoma after surgical resection.