Reinterventions for proximal conduit obstruction or on the pulmonary arteries are frequent after Sano-modified stage I Norwood palliation of hypoplastic left heart syndrome. We report our experience with a modified Sano stage I, in which the right ventricle-to-pulmonary artery (PA) conduit used is reinforced by external rings to avoid collapse, and the conduit is inserted into the right ventricle through a limited ventriculotomy and 'dunked' into the ventricular cavity. In our experience, this modification was associated with fewer reinterventions or complications with the proximal anastomosis (P = 0.046 and 0.004), improved PA pulse pressure (9.1 ± 4.1 vs 4.8 ± 3.8 mmHg in controls, P < 0.001) and Nakata index (213 ± 76 vs 134 ± 68 mm(2)/m(2) in controls, P < 0.0001), although overall survival to a median of 20 months was not significantly different from controls. Right ventricular function at stage II-bidirectional Glen was marginally better in patients with the modified Sano conduit, however not to a significant level. Further evaluation of late ventricular function is currently ongoing.