No study describes the use of extracorporeal membrane oxygenation (ECMO) in pediatric patients with abdominal sepsis (AS) requiring surgery. A description of outcomes in this patient population would assist clinical decision-making and provide a context for discussions with patients and families. The Extracorporeal Life Support Organization database was queried for pediatric patients (30 days to 18 years) with AS requiring surgery. Forty-five of 61 patients survived (73.8%). Reported bleeding complications (57.1 vs 48.8%), the number of pre-ECMO ventilator hours (208.1 vs 178.9), and the timing of surgery before (50 vs 66.7%) and on-ECMO (50 vs 26.7%) were similar in survivors and nonsurvivors. Decreased pre-ECMO mean pH (7.1 vs 7.3) was associated with increased mortality (odds ratio, 1.49; 95% confidence interval, 1.04 to 2.14). ECMO use for pediatric patients with AS requiring surgery is associated with increased mortality and an increased rate of bleeding complications compared with all pediatric patients receiving ECMO support. Acidemia predicts mortality and provides a potential target of examination for future studies.