It is shown that the cathodic reduction of hydrogen peroxide (H2O2) on silver electrodes in acidic electrolyte can proceed by two parallel mechanisms: first, by the ＇normal＇ mechanism that has been discussed in the literature, second, by a novel mechanism proceeding at a significantly more positive potential. It is proposed that the second mechanism involves the activating adsorbate (OH)(ad), that forms in the course of the H2O2 reduction reaction as an unstable intermediate. The coverage of the electrode with (OH)(ad) increases with the rate of H2O2 reduction, i.e., the process is autocatalytic. At more negative potentials the coverage decreases as the rate of adsorbate reduction/desorption rises. This leads to a potential region of negative differential charge-transfer resistance and thus to complex dynamic phenomena, in particular to electrochemical oscillations. Model calculations based on these considerations yield the potential dependent OH-adsorption, the N-shaped current/voltage curves and current oscillations that agree well with the experimental findings.