The effect of hydrogen sulfide on the electrode kinetics of hydrogen oxidation in (62 + 38)mol% (Li + K)CO3 melt at 650-degrees-C was investigated at Au, Cu and Ni electrodes using cyclic voltammetry, electrochemical impedance spectroscopy and chronocoulometry. Kinetic parameters such as j0, alpha and the stoichiometric number nu, which were obtained with and without 90 ppm H2S in a simulated fuel gas (P(H-2)/P(CO2) =0.7/0.3), were compared with each other to study the poisoning effect of H2S on the electrode kinetics. X-ray diffraction studies on the electrode surfaces exposed to the melt with H2S proved that the electrode materials used in this work stayed in the metallic state around the open-circuit potential (OCP). Cyclic voltammograms for Cu and Ni electrodes showed the formation of metal sulfides at potentials more positive (approximately 100 mV) than the OCP. However, they were re-reduced to metallic states around the OCP. The poisoning effect due to sulfide formation was not observable in the kinetic study carried out around the OCP, and another poisoning effect on electrocatalysis, supposedly due to the molecular level adsorption of sulfide ions on the electrode surface, is extremely weak, not exerting any serious retardating effect on the rate of hydrogen oxidation.