Since 1978 we have treated 26 patients with testicular cancer in stage IV with the following chemotherapy regimen: Vinblastine 6 mg/m2 (day 1 and 2) and bleomycin 30 mg given over 24 hour period (day 1 to day 5). After two cycles this therapy was changed and patients received the combination adriamycin 60 mg/m2 (day 1) and cis-DDP 20 mg/m2 (day 1 to 5) for further two cycles. We achieved 69% (18 of 26 patients) complete remissions. Patients without response or no change received as second treatment modality vincristine 0,8 mg/m2 (day 1) and ifosfamide 1500 mg/m2 (day 1 to 5). Before each chemotherapy in an interval of two days 1 Unit (= 1 KE) of OK-432 (Streptococcus pyogenes) preparation, an immunomodulating agent, was given intravenously. In the therapyfree interval of chemotherapy 2 KE of OK-432 were applied. The maintenance therapy for 1 year consisted of vinblastine and trofosfamide and also OK 432. For the achievement of complete remissions 4 courses of chemotherapy seemed to be sufficient. The inclusion of OK 432 immunotherapy in an already established chemotherapy regimen seems to be qualified due to the reduction of chemotherapy induced side effects (myelosuppression, immunodeficiency) and the immunorestoration achieved before chemotherapy.