Electrochemical oxidations of methanol were compared on smooth or high area platinum, platinum\tin and platinum\ruthenium electrodes. On smooth platinum, while ruthenium promoted the catalytic activities steadily according to the coverage, tin showed an enhancing effect only for a short period of time because of the dissolution of tin from the surface. On high area platinum, tin seemed much stabler and exhibited long-lasting enhancing effects as well as ruthenium. The reasons for the inconsistent effects of tin among past studies are discussed.