The anodic charge transfer during the production of iron by Molten Oxide Electrolysis in an Al2O3-MgO-SiO2 electrolyte has been investigated at 1793 K in dependence of the iron oxide concentration. Experiments were performed at laboratory scale using an asymmetric electrode configuration. The kinetic relation to the cell voltage was analyzed by a stepped linear scan voltammetry at various iron oxide concentrations up to 15 wt%. Complementary gas analysis allowed the derivation of the oxygen production yield. The obtained results show an electronic contribution to the overall conduction. This contribution diminishes in proportion with increasing iron oxide concentration. Charge transfer at the anode is accomplished by the oxidation of ferrous iron ions and of oxide anions. Conditions for the electrochemical charge transfer to occur solely by the oxidation of oxide anions exist for a limited cell voltage range at iron oxide concentrations of less than 10 wt%. For these concentrations a mass transfer limitation of oxide anions was detected with increasing cell voltage. However, a limit of the total current is absent as ferrous iron participates to the anode charge transfer at cell voltages above the mass transfer limitation of oxide ions. (C) 2019 The Electrochemical Society.