Our knowledge of the pathophysiology of pediatric voiding dysfunction is strengthened by urodynamic studies investigating common bladder problems in children. Natural filling urodynamics in infants and children are showing very high detrusor voiding pressures and a transient period of vesicourethral discoordination. Vesicoureteral reflux is often linked to high voiding pressure, especially in males, and the presence or absence of a pop-off has significant implications for long-term bladder function in boys with posterior urethral valves. The long-held theory of spinal reflex-mediated micturition in infants is questioned and new body surface area based nomograms for uroflowmetry in children are presented. This review illustrates the vital role urodynamic studies are playing in the diagnosis and treatment of vesicourethral dysfunction in children.