Advances in surgical technique and medical surveillance have improved outcomes of single ventricle (SV) palliation, particularly during the first interstage period. However, there remains a considerable mortality risk beyond this period. Patients born between January 2004 and December 2011 who required SV palliation were retrospectively identified. Patients who survived stage 1 palliation, were discharged home, and then were evaluated for Glenn candidacy, and continued care at our institution were included. Perioperative echocardiographic, hemodynamic, and operative data were analyzed at each surgical stage. The primary outcome was death or need for transplant. Univariate and multivariate analysis was completed using Cox proportional-hazards modeling. A total of 175 patients were included. Three patients died after pre-operative evaluation before Glenn. Glenn was completed in 168 patients, 16 died before Fontan. Fontan was completed in 149 patients; 117 were alive without need for transplant, 17 died post-Fontan, and 1 required transplantation. Twenty-one patients were lost to follow-up throughout the study period and were censored at time of last follow-up. Pre-Glenn moderate or severe atrioventricular valve regurgitation (AVVR) was an independent risk factor for death/transplant (HR 2.41; p -value.026). Pre-Glenn moderate ventricular dysfunction was also an independent risk factor (HR 5.29; p -value.012). Other risk factors included right ventricular (RV) dominant morphology and perinatal acidosis. Despite advances in SV palliation, a subset of these children remains at increased risk for poor outcomes. Early risk factors include RV dominant morphology and perinatal acidosis. Patients with substantial AVVR or ventricular dysfunction before Glenn palliation are also at significantly higher risk for death or requirement of transplantation later in childhood. [ABSTRACT FROM AUTHOR]