A case of choriocarcinoma responding well to cis-diamminedichloroplatinum (CDDP) was reported. A 24-year-old male was admitted to our hospital with chief complaints of upper abdominal discomfort and gynecomastia. Physical findings on admission included solid tumors in the upper abdomen and bilateral inguinal regions. The chest X-ray picture showed numerous coin lesions, and abdominal ultrasound examination revealed a widespread metastasis in the retroperitoneum. Blood chemical analysis pointed out the high levels of LH, HCG, and beta-subunit of HCG. The pathological diagnosis of the biopsied inguinal mass was choriocarcinoma. The patient was treated with CDDP, vincristine and bleomycin according to the protocol of Einhorn. After three courses of this therapy, serum HCG level was normalized and pulmonary metastatic lesions were diminished, although abdominal ultrasound examination showed remnants of the decreased tumor masses. The patient was transferred to the urological department for further cytoreductive therapy.