The electrocatalytic behaviour of carbon-supported ruthenium oxide electrodes for oxygen evolution and methanol oxidation in acid solutions is reported. Physical characterization of the electrodes by X-ray diffraction, X-ray photoelectron and 99Ru Mossbauer spectroscopies indicated the ruthenium to be present as a mixture of RuIV oxides including the stable rutile phase. Electrochemical studies show that a RuVI species promotes the catalytic oxidation of methanol, whilst surface-bound RuO4 is involved in the oxygen evolution reaction.