Dose intensification of the most active drugs may improve the treatment results of patients (pts.) with far advanced metastatic testicular cancer. At Hannover University pts. with advanced testicular cancer (Indiana University criteria) were entered in a phase I/II study of a step-wise dose-intensified regimen of platinum, etoposide, and ifosfamide (PEI) with s.c. GM-CSF (5-10 micrograms/kg/day). Due to thrombocytopenia and mucositis the MTD was reached at dose level 3 with P 30 mg/m2, E 200 mg/m2, and I 1.6 g/m2 (d 1-5, q 21 d, 4 cycles). Overall, 49 of 75 pts. (65.3%) achieved CR/NED. 11 pts. (14.6%) failed PEI therapy, but 4 of these achieved CR/NED by salvage treatment. After a median follow-up of 22 months 66% of pts. are alive and free of disease. The dose intensity was 1.42 compared to a standard PEI regimen. A further increase of dose-intensity will require additional haematopoietic support, e.g. peripheral blood stem cells (PBSC). PBSC following dose-intensified PEI-chemotherapy plus G- or GM-CSF are used in the current study of the German Testicular Cancer Study Group for the treatment of advanced germ cell tumours.