Endodermalsinus tumors are rare and belong to the group of malignant gem cell tumors. Histogenetically they are differently interpreted. Their unfavorable prognosis is to be attributed to existing uncertainties regarding therapeutical procedure and to the rapid tumor expansion. Our case of an advanced endodermalsinus tumor of the right ovary was operated on palliatively and then subjected to antineoplastic chemotherapy with adriamycine, bleomycine and vincristine, subsequently with actinomycine D and vinblastine. There was a complete remission of the tumor. The patient survived for 43 months free of tumor.