From July 1989 to June 1994 23 modified Blalock-Taussig shunts were performed using allograft saphenous veins. Veins stored in Hank's solution were implanted in 8, and cryopreserved ones were used in 15 cases. No operative death, bleeding, or infectious complication has occurred. There were 2 early and 2 late deaths, none was related to shunt occlusion. Clinical, angiographic and echocardiographic investigations proved that the rest of the shunts are still patent and functioning well after an average of 30 months follow up. Histological studies showed that donor cells have been replaced after several months with recipient cells both in the wall and at the luminal surface of the grafts. No difference was found between veins stored in Hank's solution and cryopreserved grafts concerning clinical outcome and histology.