Choreoathetosis developed after bilateral bidirectional cavopulmonary anastomosis in a 17-month-old boy with univentricular heart. To avoid exacerbating this neurologic problem, the Fontan operation was later completed without cardiopulmonary bypass. The left cavopulmonary anastomosis maintained pulmonary blood flow. A tube graft was anastomosed to the junction of the right cavopulmonary anastomosis. A femoral vein-to-right atrial shunt was established, the inferior vena cava divided, the cardiac end oversewn, and the noncardiac end anastomosed to the tube graft.