Platinum and platinum-tin alloy dispersed on active carbon are used as the catalysts for methanol electro-oxidation. Gas chromatographic and X-ray powder diffraction analysis show that the co-existence of Pt/C and PtSn/C in the catalysts yields better catalysis for methanol electro-oxidation than Pt/C alone. The electrochemical behaviour of the electrodes made from catalysts Pt/C and Pt-PtSn/C are investigated, together with platinum black for purposes of comparison. A new intermediate species is suggested to be present in the methanol electro-oxidation.