Patients surviving a Fontan operation experience dramatic symptomatic improvement, but concern remains about the long-term results of this operation. The clinical course and postoperative hemodynamic findings in 5 long-term survivors of the Fontan procedure from our institution are presented. Attention is drawn to 3 patients who required reoperation: 1 immediately for residual mild pulmonary stenosis, 1 for late onset complete heart block, and 1 for conduit valve stenosis. Review of our patients and those described in the literature reveals that all have ascites and pleural effusions as a results of high venous pressures but that this is usually a temporary problem. Late onset of obstruction to right atrial emptying has been reported in several patients in addition to ours. This raises serious concerns about the long-term fate of cloth conduits and porcine valves in this application. Although normal sinus rhythm has been thought to be essential for adequate pulmonary perfusion in these patients, it is interesting that several patients have tolerated atrial tachyarrhythmias, junctional rhythms, and even complete heart block without serious ill effects. We conclude that the Fontan procedure is extremely effective in relieving symptoms at an operative risk that is now acceptable, but these patients require very careful long-term follow-up because they are subject to a number of long-term complications.