We report a case of a pediatric Wilms' tumor presenting after a right renal injury. A 6-year-old girl presented to a nearby hospital with right back pain after a fall. An abdominal computed tomography (CT) scan revealed a right renal injury with active hemorrhaging. She was then referred to our hospital. There another CT scan and a magnetic resonance imaging (MRI) scan revealed the disappearance of the active hemorrhaging but also the presence of a large renal tumor. We performed a right nephrectomy. The renal tumor was diagnosed as a nephroblastoma. Considering dissemination by trauma, chemotherapy and radiation therapy were performed.