Venoarterial extracorporeal membrane oxygenation (ECMO) is used in cardiogenic shock refractory to inotropic support and intra-aortic balloon pump (IABP) support. Peripheral ECMO can lead to ventricular distention, and IABP can be used to mitigate these effects. The aim of this study was to quantify the effects of IABP concomitant with ECMO, under different simulated hemodynamic conditions in a mock circulatory loop. Different simulated states of isolated left ventricular (LV) failure and biventricular failure with graded LV failure severities were supported with ECMO and ECMO with IABP. The impact on left ventricular end-diastolic pressure (LVEDP), volume (LVEDV), coronary flow rate, and cerebral flow rate were evaluated. Left ventricular volumes and pressures increased from the heart failure states with the addition of ECMO. The IABP provided between 3% and 7% reductions in LVEDP and between 1% and 10% reductions in LVEDV. The addition of IABP had minimal effect on cerebral blood flow (0% to 7%), but the variable impact on coronary blood flow with increased diastolic coronary flow of 23% to 50%, but the reduction in mean coronary flow by up to 30%. The efficacy of the IABP was strongly related to ventricular contractility. This study demonstrates the need for careful IABP selection concomitant with ECMO.