A 63-year-old man underwent inguinal orchiectomy for painless enlargement of the left testis. The diagnosis of malignant gonadal stromal tumor was made on the basis of morphology and immunohistochemical studies, At computed tomography there was bulky retroperitoneal metastasis, The patient then underwent retroperitoneal lymphadenectomy and received 6 courses of platinum-based chemotherapy at the end of which complete response was documented, However, at 18 months' follow-up, computed tomography revealed recurrent retroperitoneal metastasis. The patient was put on chemotherapy regimen again. But he developed pulmonary metastasis and died 28 months after the initial diagnosis. The clinical course of this patient suggests that malignant gonadal stromal tumor, if metastatic at diagnosis, may have a poor prognosis against most aggressive treatment approaches.