Most patients with Wilms' tumour in Europe and North America can be cured with treatment and subsequently lead a normal adulthood. However, for some, therapy as applied today results in long-term side-effects and creates a substantial burden on quality of life. Therefore, investigators involved in the management of patients with Wilms' tumour are increasingly focusing their efforts on curtailing the long-term sequelae of therapy. This aim has been achieved by lowering the total amount of chemotherapy, radiotherapy, or both administered to patients who have characteristics associated with favourable outcome. Although excellent survival has been maintained, many patients receive less therapy today than patients with similar characteristics did a decade or two ago. Better understanding of the biological processes that lead to this childhood cancer will allow further improvements in its management.