The process of placing a patient on venoarterial extracorporeal membrane oxygenation (VA-ECMO) is complex and requires the activation and coordination of numerous personnel from a variety of disciplines to achieve procedural success, initiate flow, and subsequently monitor the patient’s condition. The literature suggests that nighttime cannulation for extracorporeal cardiopulmonary resuscitation (ECPR) is associated with adverse outcomes compared to daytime cannulation. Given the strain on personnel that this process can create, it is plausible that patients who are initiated on VA-ECMO for non-ECPR indications during the nighttime and on weekends, which are generally periods with reduced staffing compared to weekday daytime hours, also may experience worse outcomes, including decreased survival. This study aimed to determine whether nighttime/weekend VA-ECMO cannulation is associated with worse outcomes, including decreased survival.