INTRODUCTION: The use of extracorporeal membrane oxygenation (ECMO) in congenital heart disease is mostly well established. ECMO has served as a bridge to recovery, decision or transplant in the setting of myocardial decompensation. ECMO has provided support for single ventricle patients at different postoperative stages of the palliation. Little is known regarding the use of preoperative ECMO support in this population. We aim to evaluate the outcomes of patients with single ventricle physiology supported with ECMO as a bridge to palliation. METHODS: Data was collected from the Extracorporeal Life Support Organization (ELSO) registry between 2016 to 2021. Patients were included in the study if they had single ventricle physiology and required ECMO support prior to their first stage palliation. Multiple variables including demographics, pre ECMO course, indications for ECMO, cannulation details, ECMO duration, course, complications and survival to hospital discharge data were collected. Descriptive statistics and student t-test was used to compare continuous variables. Dichotomous variables were compared using chi square and fisher tests. A p-value of 0.1 was considered as statistically significant in univariate analysis. RESULTS: Sixty-six patients met inclusion criteria. Of the 66 patients, 24 died on ECMO prior to first stage palliation (36%). Thirty-nine of the 66 patients died before discharge (59%). There was no significant difference in weight and age between patients who died and survived on ECMO. Patients who died on ECMO had significantly longer ECMO runs than those who survived (248 hrs vs. 115 hrs; p < 0.001) . Patients who died on ECMO were significantly more likely to have a higher initial paO2(49 mmHg vs. 40 mmHg; p=0.027) and oxygen saturation (77% vs. 69%; p=0.076) than those who survived. Patients who died on ECMO were significantly more likely to have more than four complications during their course than those who survived (63% vs. 17%; p < 0.001). CONCLUSIONS: A third of patients supported with ECMO prior to initial single ventricle palliation died on ECMO. Those who died on ECMO were significantly more likely to undergo a longer ECMO run, suffer more complications, have a higher initial paO2 and oxygen saturation than those who survived ECMO. This information may guide management in the future.