The kinetics of H2 oxidation reaction on Pt-black/Nafion thin-film electrodes in 0.5 M H2SO4 at 298 K was investigated using the rotating disk electrode (RDE) technique. The Nafion coating (≦8.0 μm) had a negligible effect on the electrochemical active surface area measured. The equation describing the H2 oxidation kinetics on the thin-film RDEs was derived and the kinetic parameters were determined. The H2 oxidation was very facile and the current density was determined by the mass transfer of H2 in the aqueous electrolyte and the Nafion film. The results of this study are useful for designing the electrodes for fuel cells using Pt-black catalyst.