<title>Abstract</title> Background: Cerebral perfusion may change depending on arterial cannulation site and may affect the incidence of neurologic adverse events in post-cardiotomy extracorporeal life support (ECLS). The current study compares patients' neurologic outcomes with three commonly used arterial cannulation strategies (aortic [A] vs. subclavian/axillary [SA] vs. femoral [F] artery) to evaluate if each ECLS configuration is associated with different rates of neurologic complications. Methods: This retrospective, multicenter (34 centers), observational study included adults requiring post-cardiotomy ECLS between January 2000 and December 2020 present in the Post-Cardiotomy Extracorporeal Life Support (PELS) Study database. Patients with Aortic, Subclavian/Axillary and Femoral cannulation were compared on the incidence of a composite neurological end-point (ischemic stroke, cerebral hemorrhage, brain edema). Secondary outcomes were overall in-hospital mortality, neurologic complications as cause of in-hospital death, and post-operative minor neurologic complications (seizures and vasospasm). Association between cannulation and neurological outcomes were investigated through mixed-Cox proportional hazards models. Results: This study included 1897 patients comprising 26.5% A (n=503), 20.9% SA (n=397) and 52.6% F (n=997) cannulations. The SA group featured a more frequent history of hypertension, smoking, diabetes, previous myocardial infarction, dialysis, peripheral artery disease and previous stroke. Neuro-monitoring was used infrequently in all groups. Major neurologic complications were more frequent in SA (A: n=79, 15.8%; SA: n=78, 19.6%,; F: n=118, 11.9%; p&lt;0.001). Seizures were more common in SA (n=13, 3.4%) than A ( n=9, 1.8%) and F cannulation (n=12, 1.3%, p=0.036). In-hospital mortality was higher after A cannulation (A: n=344, 68.4%, SA: n=223, 56.2%, F: n=587, 58.9%, p&lt;0.001), as shown by Kaplan-Meier curves, with more patients deceased during ECLS support. Anyhow, neurologic cause of death (A: n=12, 3.9%, SA: n=14, 6.6%, F: n=28, 5.0%, p=0.433) was similar. Conclusions: In this analysis of the PELS Study, SA was associated with higher rates of major neurologic complications and seizures. In-hospital mortality was higher after A cannulation, despite no significant differences in incidence of neurological cause of death in these patients. These results encourage vigilance for neurologic complications and neuromonitoring use in patients on ECLS, especially with SA cannulation.