To assess the results of cardiac repair utilizing a right ventricular to pulmonary artery conduit, we reviewed postoperative hemodynamic data in 16 patients catheterized 0.5 to 5 years after repair. In 12 patients, a Hancock conduit (dacron conduit with porcine valve) was used; the conduit in the remaining four patients was made with an aortic homograft. All patients in whom an aortic homograft was utilized developed severe obstruction and calcification of their graft. The majority of patients, 9/12, with a Hancock conduit, had only mild to moderate conduit obstruction; the remaining three had severe obstruction (gradients greater than 70 mm Hg). The sites of Hancock conduit obstruction were at the distal end of the conduit in 8/12, proximal end of conduit in 6/12, and at the porcine valve in 4/12 patients. The data suggest that repair with a Hancock conduit is hemodynamically more satisfactory than with aortic homograft.