The electrode polarization behavior of iron and austenitic stainless steels 304 and 316 was studied in molten sodium carbonate at 1000°C under an atmosphere of 24% CO, 24% CO 2, 49.3% H 2 and 2.7% H 2S at 1 atm. The empirical polarization data were fitted to a previously described analytical model incorporating the effects of electron transfer polarization, concentration polarization and ohmic loss. Three distinct anodic reactions were seen. Comparison of curve parameters with results from a previous study of the nickel electrode together with analyses of anodic scales and expected equilibria in the system indicate that these reactions, in order of increasing anodic overpotential, are the oxidation of iron to the Fe 2+ state with the formation of FeO, the oxidation of iron and chromium to the 3+ state with the formation of the spinel oxide FeFe 2−xCr xO 4, and the oxidation of CO 3 2− with formation of O 2. The only distinction in the behavior of the iron and stainless steel electrodes is in the composition of the spinel oxide and a Nernstian displacement of the reaction Fe = Fe 2+ + 2 e. In addition to these significant electrode reactions, carburization of iron was seen at cathodic potentials, with oxidation of the carbide at anodic potentials.