Within the last 20 years 43 children with Wilms' tumour were seen at the Paediatric Departments of the University Hospitals of Graz, Innsbruck and Vienna. Case histories, clinical details and diagnostic procedures are discussed. Since 1969 19 out of 21 children were treated according to the modern atandard regimen (operation, irradiation and cytostatic therapy for 2 years except in infants with stage I). Since 1969 the survival rate has been higher (17 out of 21 children: 81%) than in the period 1956 to 1968 (7 out of 22 children: 31.8%), when only one child (in stage I) was treated according to current concepts. The better prognosis noted in young infants of this series, as in the literature was due to the earlier stage of the disease in these infants. A further improvement in the survival rate of children with Wilms' tumour should be achieved by earlier diagnosis, thereby ensuring operability, and by cytostatic therapy during the following 2 years. This will only be possible when there is closer cooperation between surgeon, radiotherapist and oncologist. It should be possible to lower the long-term therapeutic complication rate with even more stringent observation measures and with increasing expertise of all doctors concerned.