We report a case of multiple neurinomas arising in the posterior mediastinum and the retroperitoneum. A 49-year-old man was admitted to our department for operation after an abnormal shadow appeared on routine chest X-ray film. A left adrenal tumor was found incidentally with ultrasonography at the time of a previous thoracic surgery. First, the posterior mediastinal tumor was surgically removed. Histologic diagnosis was neurinoma. After resection, endocrinologic findings were within normal limits. A left adrenal tumor was diagnosed, and surgery was performed. The tumor was separated from the adrenal gland; the histologic diagnosis was neurinoma. Neurinomas are usually solitary; multiple neurinomas are extremely rare.