Modifications of the Fontan operation can afford excellent palliation for many patients with a variety of forms of single ventricle. In properly selected patients who are good candidates, early and late survival can be as high as 95–97%. However, mortality is considerably higher for patients with risk factors for poor outcome. For high-risk patients, inclusion of a fenestration may reduce morbidity and mortality. Important long-term undesirable events include the ongoing risk of death, arrhythmias, protein-losing enteropathy, and cardiac failure. The key to excellent long-term outcome is proper selection of patients for the operation.