Portocaval fistulas are rare and only exceptionally discovered in newborns. We report the case of a large portocaval fistula associated with portal hypoperfusion detected at Doppler US imaging in an otherwise asymptomatic 5 week old infant. The patient remained asymptomatic over the following two years. At that time, preoperative angiogram showed a normal portal venous system and the fistula was surgically closed. Postoperative US showed a normal and patent portal system, without evidence of portal hypertension.