The electro-oxidation of methanol was studied in acid media at iridium electrodes modified by the electrochemical deposition of hydrated iridium oxide. This oxide was grown by the repetitive cyclic polarization technique. The influence of methanol concentration, solution composition and temperature, and the number of the cycles applied to form the oxide on the oxidation current density have been studied voltammetrically. This electrode behaves as an electrocatalyst for the electro-oxidation of methanol. The mechanism of oxidation is likely to be dissociative chemisorption involving one electron transfer. The rate constant for the oxidation of methanol is 3.5 x 10(-8) mol s(-1) cm(-2) at 1.20 V vs see.