Despite the remarkable success in treatment of Wilms' tumour there is still a small group who will suffer from relapse. The optimal therapy for relapsing Wilms tumour has not been determined. We have treated four children with high-dose chemotherapy (HDC) followed by stem-cell support known as autologous bone marrow transplantation (ABMT). The patients were two girls and two boys aged 1-9 years. The histology was favourable in 3 cases and unfavourable, clear cell sarcoma, in 1. The relapses were pulmonary in 2 cases and skeletal in 2 cases. There was no detectable disease prior to ABMT. After ABMT 2 children got further relapses and died. On the other hand 2 children had no further relapse and are alive and well 1.5-2.5 years later. Treatment with HDC and ABMT is complicated and expensive but may be of benefit and should be added to the treatment options in children with otherwise poor prognosis of Wilms' tumour.