Objectives: Although cardiogenic shock requiring extracorporeal life support after cardiac surgery is associated with high mortality, the impact of sex on outcomes of postcardiotomy extracorporeal life support remains unclear with conflicting results in the literature. We compare patient characteristics, in-hospital outcomes, and overall survival between females and males requiring postcardiotomy extracorporeal life support. Methods: This retrospective, multicenter (34 centers), observational study included adults requiring postcardiotomy extracorporeal life support between 2000 and 2020. Preoperative, procedural, and extracorporeal life support characteristics, complications, and survival were compared between females and males. Association between sex and in-hospital survival was investigated through mixed Cox proportional hazard models. Results: This analysis included 1823 patients (female: 40.8%; median age: 66.0 years [interquartile range, 56.2-73.0 years]). Females underwent more mitral valve surgery (females: 38.4%, males: 33.1%, P = .019) and tricuspid valve surgery (feamales: 18%, males: 12.4%, P < .001), whereas males underwent more coronary artery surgery (females: 45.9%, males: 52.4%, P = .007). Extracorporeal life support implantation was more common intraoperatively in feamales (females: 64.1%, females: 59.1%) and postoperatively in males (females: 35.9%, males: 40.9%, P = .036). Ventricular unloading (females: 25.1%, males: 36.2%, P < .001) and intra-aortic balloon pumps (females: 25.8%, males: 36.8%, P < .001) were most frequently used in males. Females had more postoperative right ventricular failure (females: 24.1%, males: 19.1%, P = .016) and limb ischemia (females: 12.3%, males: 8.8%, P = .23). In-hospital mortality was 64.9% in females and 61.9% in males (P = .199) with no differences in 5-year survival (females: 20%, 95% CI, 17-23; males: 24%, 95% CI, 21-28; P = .069). Crude hazard ratio for in-hospital mortality in females was 1.12 (95% CI, 0.99-1.27; P = .069) and did not change after adjustments. Conclusions: This study demonstrates that female and male patients requiring postcardiotomy extracorporeal life support have different preoperative and extracorporeal life support characteristics, as well as complications, without a statistical difference in in-hospital and 5-year survivals.