In children with febrile urinary tract infections (UTI) it is estimated that between 28% and 36% have vesicoureteral (VUR) to some extent. The prevalence is higher in younger children range due to the propensity of VUR to improve or resolve with age. Such is the heritability of the condition that approximately 15% of siblings of an index case of VUR in a family will have VUR. From a pathophysiology standpoint, VUR can be thought of as being primary, due to anatomical factors related to ureteral implantation into the trigone, or secondary, which occurs in response to raised intra-vesical pressure. The radiological classification of VUR depends on the mode of imaging. The fluoroscopic classification derived from the International Study of Reflux in Children grades VUR from grade I to grade V, with grades I–II representing non-dilating VUR and grade III–V representing dilating VUR. The clinical behaviour and natural history of non-dilating VUR vs dilating VUR differ significantly. A separate, less granular, classification system exists for VUR diagnosed by radionuclide cystography.