In the German Society of Pediatric Oncology (GPO) designed in 1982 a cooperative study to improve the outlook of patients with malignant testicular germ cell tumors. According to stage and histology of the tumor different surgical approaches to retroperitoneal lymphadenectomy are outlined. Local radiotherapy is not recommended. Adjuvant chemotherapy with Vinblastine, Bleomycin and CIS-Platinum is proposed. Up to 1987 27 YST, 3 MTI, 6 MTU, 1 MTT and 9 TD were treated. Only one patient with YST had a relapse; one patient died from candida septicemia. Alternative chemotherapy was given 3 times. Overall toxicity from treatment was mild. So far the combined modality therapy was found to be effective to increase the relapse free survival.