This prospective phase II study assesses the clinical efficacy and complications of a treatment regimen comprising combination chemotherapy with carboplatin and ifosfamide and selective consolidation in advanced seminoma. Of 43 patients who entered the study, between May 1989 and May 1992, 42 were evaluable. 30 achieved a complete remission (71%; 95% confidence interval, 56-84%) after chemotherapy alone. 10 achieved a complete remission (24%; 95% confidence interval, 13-39%) after chemotherapy plus consolidation. 38 of the 42 patients (91%; 95% confidence interval, 83-98%) remained in remission after a median follow-up period of 35 months (20-56 months). No patient experienced nephrotoxic, neurotoxic, or ototoxic effects, or haemorrhagic cystitis. Ten per cent of the patients had leucopenic fever requiring hospitalisation. Twenty-four per cent required platelet transfusions, and 26% required transfusions of packed red blood cells. For patients with seminoma, treatment with carboplatin and ifosfamide and selective consolidation is safe and effective.