Background: Patients with venoarterial extracorporeal membrane oxygenation (VA-ECMO) are at risk of cerebral reperfusion injury after prolonged hypoperfusion and immediate restoration of systemic blood flow. We aimed to examine the impact of mild hypothermia during the first 24 hours post-ECMO on neurological outcome in VA-ECMO patients. Methods: This was a retrospective study of adult VA-ECMO patients from a tertiary care center. Mild hypothermia was defined as 32-36°C during the first 24 hours post-ECMO. Primary outcome was good neurological function at discharge measured by a modified Rankin Scale ≤3. Multivariable logistic regression analysis was performed for primary outcome adjusting for pre-specified covariates. Results: Overall, 128 consecutive patients with VA-ECMO support (median age: 60 years and 63% males) were included. Within the first 24 hours of VA-ECMO cannulation, we found a median of 71 readings per patient (interquartile range 45-88). Eighty-eight patients (68.8%) experienced mild hypothermia within the first 24 hours while 18 of those 88 patients (14.2%) had a mean temperature<36°C. ECMO indications included post-cardiotomy shock (39.8%), cardiac arrest (29.7%), and cardiogenic shock (26.6%). Duration of mild hypothermia, but not mean temperature, was independently associated with increased odds of good neurological outcome at discharge (Odds Ratio [OR]=1.16, 95% Confidence Interval [CI]=1.04-1.31, p=0.01) after adjusting for age, severity of illness, post-ECMO systemic hemorrhage, post-cardiotomy shock, acute brain injury, and mean 24-hour PaO 2. Neither duration of mild hypothermia (OR=0.93, CI=0.84-1.03, p=0.17) nor mean temperature (OR=0.78, CI=0.29-2.08, p=0.62) was significantly associated with mortality. Similarly, duration of mild hypothermia (p=0.47) and mean 24-hour temperature (p=0.76) were not significantly associated with frequency of systemic hemorrhages. Conclusions: In this single center study, longer duration of mild hypothermia during the first 24 hours of ECMO support was significantly associated with improved neurological outcome. Mild hypothermia was not associated with an increased risk of systemic hemorrhage or improved survival.