Due to the close interdisciplinary work of surgeons, radiologists and oncologists, the prognosis for Wilms' tumor (the most common renal tumor in childhood) has been dramatically improved over the last few decades. The treatment of such tumors is currently carried out worldwide by two study groups, in North America the National Wilms' Tumor Study (NWTS) and in Europe the Society of Paediatric Oncology (SIOP). Here we present an overview of the current treatment results and discuss future diagnostic and therapeutic strategies.