Few data describe pediatric patients who receive massive transfusion for life-threatening hemorrhage (LTH) while on extracorporeal membrane oxygenation (ECMO). We present a retrospective secondary analysis of a multicenter prospective observational study to describe resource utilization and mortality in pediatric patients with LTH while on ECMO. Children who were on ECMO during an LTH were compared to children with LTH who were not on ECMO. Primary outcomes were volumes of blood products administered and 28 day mortality. Comparisons were assessed by two-sided Fisher’s exact test or Wilcoxon rank sum test. A total of 449 children, including 36 on ECMO, were included. Compared to those not on ECMO, children on ECMO received a higher volume of blood products (110 [50–223] vs. 59 [28–113]) ml/kg, p = 0.002) and were more likely to receive antifibrinolytic therapy (39% vs. 10%, p < 0.001). Blood product ratios were similar. Extracorporeal membrane oxygenation patients had higher 28 day mortality (64% vs. 35%, p = 0.001), although 24 hour mortality was similar (17% vs. 23%, p = 0.5). In conclusion, children on ECMO with LTH experience high resource utilization and 28 day mortality. Studies are needed to identify children at risk for LTH and to evaluate ECMO-specific treatment strategies.