33 patients (median age 39 years) with advanced seminoma were treated with 4 courses of alternating cisplatin-containing chemotherapy PVB/BEP (cisplatin, vinblastine and bleomycin; bleomycin, etoposide and cisplatin). Patients were classified as stage IIC (n = 7), IID (n = 9), III (n = 13) and IV (n = 4). 8 had had prior radiotherapy; 9 had an elevated beta human chorionic gonadotropin (beta HCG). 30 patients were evaluable for response and 33 for toxicity. During chemotherapy 3 patients died, 1 due to malignant disease, another due to a cardiac arrest, and 1 patient of a bleomycin pneumonitis. 13 (43%) had a complete remission and 17 (57%) had a clinical partial remission (residual radiographic mass). At a median follow-up of 28 months (range 16-88), 3 patients relapsed, 6-8 months after entry. After completion of therapy there were 2 deaths, 1 due to bleomycin pneumonitis and 1 neither tumour nor treatment related. 26 of 33 (79%) patients achieved a continuously disease-free status. Leucocytopenia and thrombocytopenia of WHO grade 3/4 occurred in, respectively, 32/33 (97%) and 20/33 (61%) of the patients. This study shows that alternating PVB/BEP in this group yields comparable response rates with non-alternating schedules but at the expense of considerable toxicity.