A 40-year-old male with anterior mediastinal germinoma, who had developed cardiac tamponade, was treated with two courses of chemotherapy consisting of CDDP, Vindesine, Pepleomycin. After marked decrease of tumor size was obtained, complete surgical resection was performed. Following the operation, he received one more course of chemotherapy and 40 Gray of radiation therapy. He is now in good health 7 months after operation without showing any sign of recurrence. This case was also associated with right aortic arch and congenital subclavian steal phenomenon. These rare anomalies were reported only some 40 cases in the literature and the case with those rare anomalies and the mediastinal tumor was not seen in the literature.