Wilms’ tumour (nephroblastoma) ist the most common malignant kidney tumour in childhood with an incidence of 0.8/100,000 children below the age of 15 years. Boys and girls are affected with equal frequency. Peak incidence is between the 2nd and 4th year of life. This tumour is frequently accompanied by certain malformations. Familial cases occur in about 1% of all cases. A bilateral nephroblastoma is found in 5% of the patients. The pre-operative diagnosis of Wilms’ tumour is based on imaging studies and confirmed by histology. Treatment should be performed according to prospective multicentre studies, like the SIOP studies in Europe or the NWTS studies in North America. The SIOP favours a pre-operative chemo-therapeutic approach, whereas the NWTS starts treatment with primary surgery of the tumour. Post-operative treatment depends always on stage and histological subtype of the tumour. The most important drugs are vincristine and actinomycin D. Adriamycin is restricted to patients with higher stages or those with unfavourable histology. Second-line drugs are carbopla-tinum, VP 16 and cyclophosphamide or ifosfamide. Radiotherapy is only necessary in patients with stage II disease and lymph node involvement or higher stages, or in patients with unfavourable histology with the exception of stage I. Prognosis depends mainly on stage and histology. Today more than 85 % of all children with Wilms’ tumour can be cured. Patients with stage I disease and favourable histology have a more than 90% chance of cure. Treatment of children with unfavourable histology is still not satisfying. Because of the high cure rates attention must be drawn to possible late effects of trea