Wilms' tumor or nephroblastoma is the most common malignant tumor stemming from kidney cells and second only to neuroblastoma when it comes to extracranial solid tumors in children. The results of nephroblastoma treatment are a perfect example of therapeutic success resulting from an interdisciplinary approach to the problem and the cooperation of pediatric surgeons, pediatric oncologists, pathologists, radiologists and radiotherapists leading to precise diagnoses and the selection of the optimal treatment. At the end of the sixties, international research teams began studying the best treatment for this tumor in children. In Europe, it was the International Society of Paediatric Oncology (SIOP), which has used the working name SIOP- RTSG (Renal Tumor Study Group - Group for the Study of Kidney tumors) since 2008 and in North America NWTS (National Wilms' Tumor Study - The National Committee for Research on Wilms' tumor). Summarizing the experience and knowledge on the treatment of nephroblastoma, it should be noted that, despite years of research and information exchange, uniform guidelines have not yet been developed, and there are still differences in treatment of this tumor. The biggest differences are between the "American" treatment recommended by the NWTS and the "European" by SIOP. In the first it is recommended to start treatment from the surgical removal of the tumor, even in the case of disseminated disease with the presence of metastases in the lungs. The treatment method is chosen by the institution managing the patient; for this reason on the American continent in Brazil, Wilms' tumor is treated according to the recommendations of "European" protocols (SIOP) and some institutions in Europe, for example in Italy, treat patients with nephroblastoma according to the "American" protocols recommended by the NWTS; until recently, focal disease was treated with primary nephrectomy in the UK.