The kinetics of the Fe/Fe2+ electrode have previously been explained on the basis of either a consecutive or a catalytic charge transfer mechanism including adsorbed intermediates. In order to obtain more exact kinetic information, pulse and frequency response measurements on polycrystalline Fe in acidic sulfate solutions at have been carried out. The stationary current density‐potential curves already allow a preselection of the proposed reaction models. Dynamic parameters were calculated from the measured electrode impedance. It is shown that the existing reaction models do not agree with the measured impedance behavior. However, the experimental results can be explained assuming a potential‐dependent relaxation of the surface combined with a catalyzed dissolution mechanism. The mechanism of the iron electrode in the active, transition, and prepassive ranges can be described by the reaction scheme