A one-step synthesis of adherent polypyrrole (PPy) films on zinc electrodes is achieved by electro-oxidation of pyrrole in aqueous oxalate solution containing small amounts of sulfide ion at pH 5 in either the galvanostatic or potentiodynamic modes. Very good electropolymerization coulombic efficiencies were obtained (gamma = 90%) for current densities ranging between 4 and 20 mA cm(-2)