The electrooxidation of adsorbed glycerol species on platinized platinum electrodes in 1 N H2SO4was studied by cyclic voltammetry and the potential step method. The main conclusions are: the electrooxidation of glycerol at potentials lower than 1.2 V (vs, RHE) is a complex reaction in which more than one adsorbed intermediates are probably involved. The adsorbed intermediates exhibit ageing effects, at higher potentials a chemical interaction between glycerol and adsorbed oxygen occurs and the overall process is controlled by mass transfer.