The effect of Ge4+ ions, a deleterious impurity for zinc deposition in acidic sulfate electrolytes, and that of Pb2+ ions, which inhibit hydrogen evolution, have been investigated by means of steady-state polarization curves and impedance analysis. Typical impedance plots have been shown to characterize the processes of zinc deposition, hydrogen evolution on zinc, and hydrogen evolution on adsorbed germanium. From changes in the double layer capacitance, the charge transfer resistance and the low-frequency relaxation processes, it is concluded that lead adsorbed on zinc generates a lessened activation of hydrogen evolution with increasing cathodic potential, and enhances the formation of Had on the zinc deposit. With the addition of Pb2+ ions to the Ge4+-containing electrolyte, the features characteristic of zinc deposition are observed to prevail in the electrode impedance.