Beckwith-Wiedemann syndrome is a somatic overgrowth syndrome characterized by a variable incidence of congenital anomalies, including hemihypertrophy, omphalocele, macroglossia and renal malformations. We report a child with Beckwith-Wiedemann syndrome and posterior urethral valves. Urethral valve resection was successfully performed under general anesthesia after voiding cystourethrography. This is the first report of Beckwith-Wiedemann syndrome associated with posterior urethral valves.