An intact atrial septum places infants with hypoplasia of the left heart into a group with an extremely high rate of mortality. We report a neonate, diagnosed antenatally, who was delivered by Caesarian section in the cardiac theatre, urgently placed onto cardiopulmonary bypass, and who then underwent an atrial septectomy and banding of both pulmonary arteries. After stablilisation, his arterial duct was stented, completing the first stage of hybrid palliation.