The electrochemical kinetics for the oxidation of methanol to CO2 in the low overpotential region on platinum have been measured, whilst simultaneously monitoring the coverage of the electrode with adsorbed CO, Attack on adsorbed CO by water appears to be the rate-limiting process for smooth polished platinum, whereas migration of the CO to active sites limits the reaction rate for electrochemically roughened platinum. It is clear that adsorbed CO helps to stabilize the roughened platinum surface, allowing oxidation of methanol to take place at significantly lower overpotentials.