The German Society of Pediatric Oncology (GPO) designed 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 suggested. Local radiotherapy is not recommended. Adjuvant chemotherapy with Vinblastine, Bleomycin and Cis-Platinum according to stage of disease, histologic classification and age of the patient is outlined. For non-responders or patients with only partial response an alternative aggressive chemotherapy with VP 16, Ifosfamide and Cis-Platinum is guidelined.