BACKGROUND The use of venoarterial extracorporeal membrane oxygenation (va-ECMO) via peripheral cannulation for septic shock is limited by blood flow and increased afterload for the left ventricle. CASE REPORT A 15-year-old girl with acute myelogenous leukemia, suffering from severe septic and cardiogenic shock, was treated by venoarterial extracorporeal membrane oxygenation (va-ECMO). Sufficient extracorporeal blood flow matching the required oxygen demand could only be achieved by peripheral cannulation of both femoral arteries. Venous drainage was performed with a bicaval cannula inserted via the left V. femoralis. To accomplish left ventricular unloading, an additional drainage cannula was placed in the left atrium via percutaneous atrioseptostomy (va-va-ECMO). Cardiac function recovered and the girl was weaned from the ECMO on day 6. Successful allogenic stem cell transplantation took place 2 months later. CONCLUSIONS In patients with vasoplegic septic shock and impaired cardiac contractility, double peripheral venoarterial extracorporeal membrane oxygenation (va-va-ECMO) with transseptal left atrial venting can by a lifesaving option.