Mixed cardiogenic-septic shock (MS), defined as the combination of cardiogenic (CS) and septic (SS) shock, is often encountered in cardiac intensive care units. Herein, the authors compared the impact of venoarterial extracorporeal membrane oxygenation (VA-ECMO) in MS, CS, and SS. Of 1,023 patients who received VA-ECMO from January 2012 to February 2020 at a single center, 211 with pulmonary embolism, hypovolemic shock, aortic dissection, and unknown causes of shock were excluded. The remaining 812 patients were grouped based on the cause of shock at VA-ECMO application: i) MS (n = 246, 30.3%), ii) CS (n = 466, 57.4%), iii) SS (n = 100, 12.3%). The MS group was younger and had lower left ventricular ejection fraction than the CS or SS group did. The 30 day and 1 year mortalities were the highest in SS (30 day mortality: 50.4% vs. 43.3% vs. 69.0%, p < 0.001 for MS versus CS versus SS, respectively; 1 year mortality: 67.5% vs. 53.2% vs. 81.0%, p < 0.001 for MS versus CS versus SS, respectively). Posthoc analysis showed that the 30 day mortality of MS was not different from CS, while the 1 year mortality of MS was worse than CS but better than SS. Venoarterial extracorporeal membrane oxygenation application for MS may help improve survival and should therefore be considered if indicated.