The patient was a 70-year-old male with complaint of macrohematuria at the first visit to our clinic on June 10, 1986. At that time, cystoscopy revealed a thumb sized papillary tumor and a rice sized non papillary tumor, and the biopsy specimen was pathologically diagnosed as undifferentiated carcinoma. But, he refused admission. On January 30, 1987, he came back to our clinic with complaints of dyspnea, general fatigue and weight loss. Moderate lt. gynecomastia was found and the level of serum hCG-beta was detected as high as 101 ng/ml. Excretory urogram and enhanced CT revealed a large mass in the bladder. In the seventeenth day after admission, he died of lung edema and heart failure. The findings of autopsy showed a large light greenish to light brownish tumor of 10 X 10 X 3 cm in the bladder. Distant metastases were observed in internal, common iliac and paraaortic lymph nodes, but without other distant metastasis. In histological and immunohistochemical studies, the final diagnosis is choriocarcinoma of the bladder, containing syncytiotrophoblastic giant cells with hCG-beta granules as an undifferentiated carcinoma. To our knowledge this case is the eighth described in Japan. Herein we report a new case of primary choriocarcinoma of the bladder and make a brief review of the literatures.