Over the last few decades advances in the treatment of childhood and young adult cancer have greatly improved survival. As a result most children diagnosed with Wilms' tumor (the most common renal tumor in childhood) or other renal tumors become long-term survivors, living with surgically solitary kidneys. As physical activity is gaining credibility as a therapy enhancing well-being, encouraging cancer survivors do exercise during adolescence and adulthood is advisable. Discussing current evidence-based information would help to provide a framework for the harmonization of guidelines for sport participation of childhood and young adult renal tumor survivors.