Novel multilayer films containing 1:12 phosphomolybdic anions were achieved on the surface of a gold electrode by alternating deposition of 1:12 phosphomolybdic anion with water-soluble polypyrrole. The chemically-modified electrode (CME) was shown to exhibit an electrocatalytic response for the reduction of hydrogen peroxide. Hydrogen peroxide was detected by flow-injection analysis at the modified electrode with high sensitivity. The method gave a linear range from 1 X 10(-2) moll(-1) to 1 X 10(-5) moll(-1) and a detection limit of 1 X 10(-6) moll(-1) (signal-to-noise ratio 3).