A 6-years old boy who had the Endodermal Sinus Tumor of the Retroperitoneum with a large pulmonary metastatic lesion was treated by eurgical excision, poatoperative systemic chemotherapy with VAC(Vincristine, Actinomycin D, Cyclophosphamide) and local radioth- erapy at the Department of Surgery of Gospel Hospital. The patient responded very well to the combined modality of treatment with marked regression of metastatic pulmonary lesion, decreasing level of alpha-Fetoprotein and improved clinical signs. The retroperitoneal E.S.T. usually carries a grave prognosis as in other extragonadal sites. But, our experience of this case and review of literature support that E.S.T., even advanced cases, can be treated by combined modality of treatment, i.e., surgical excision, pre-and post-operative chemoteerapy and radiation therapy.