Vesicoureteral reflux (VUR) is very common in children. The close relationship with vesico-sphincter dysfunction maintains and aggravates the reflux and can have consequences on the upper renal system, hence the importance of diagnosing vesico-sphincter dysfunction at risk of vesico-ureteral reflux in order to adapt the therapeutic management of children with VUR. This evaluation requires a clinical and urodynamic assessment of the vesicosphincter system.