Vesicoureteral reflux is due to abnormalities of the ureterovesical junction. Reflux is prevented by an adequate submucosa ureter within the bladder, which acts as a passive one-way flap valve. Primary vesicoureteral reflux is due to a short submucosal tunnel and enlarged ureteral orifice. The normal and abnormal anatomy and histological findings associated with VUR are reviewed. Bladder dysfunction is associated with VUR and is a negative predictor for spontaneous resolution and a risk factor for urinary tract infections. The normal development of bladder function and the types of bladder dysfunction associated with VUR are reviewed. The importance of recognition and treatment of bladder and bowel dysfunction is reviewed.