The hemoglobin value to trigger red blood cell (RBC) transfusion for patients receiving venovenous extracorporeal membrane oxygenation (VV-ECMO) is controversial. Previous guidelines recommended transfusing to a normal hemoglobin, but recent studies suggest more RBC transfusions are associated with increased adverse outcomes. Is implementation of different institutional RBC transfusion thresholds for patients receiving VV-ECMO associated with changes in RBC utilization and patient outcomes? Single-center retrospective study of patients receiving VV-ECMO using segmented regression to test associations between implementation of institutional transfusion thresholds and trends in RBC utilization. Associations with secondary outcomes, including in-hospital survival, were also assessed. The study included 229 patients: 91 in the "no threshold (NT)" cohort, 48 in the "hemoglobin <8 g/dL (<8 g/dL)" cohort and 90 in the "hemoglobin <7 g/dL (<7 g/dL)" cohort. Despite a decrease in RBC/ECMO day following implementation of different thresholds, (mean +/- SD; 0.6 +/- 1.0 in the NT cohort, 0.3 +/- 0.8 in the <8 g/dL cohort, and 0.3 +/- 1.1 in the <7 g/dL cohort, p < 0.001), segmented regression showed no association between implementation of transfusion thresholds and changes in trends in RBC/ECMO day. We observed an increased hazard of death in the NT cohort compared to the <8 g/dL cohort (aHR: 2.08, 95% CI: 1.12-3.88), and in the <7 g/dL cohort compared to the <8g/dL cohort (aHR: 1.93, 95% CI: 1.02-3.62). There was no difference in the hazard of death between the NT and <7 g/dL cohorts (aHR: 1.08, 95% CI: 0.69-1.69). We observed a decrease in RBC/ECMO day over time, but changes were not associated temporally with implementation of transfusion thresholds. A transfusion threshold of hemoglobin <8 g/dL was associated with a lower hazard of death, but these findings are limited by study methodology. Further research is needed investigating optimal RBC transfusion practices for patients supported with VV-ECMO.