The electrocatalytic oxidation of aliphatic primary diols was investigated by means of chromatographic techniques. The formal kinetic studies showed that the reaction rate laws were changing during long-term electrolyses because of the modification of the intrinsic properties of the electrode surface. Under our experimental conditions, for all the diols investigated, from C-4 to C-7, the reaction was found to be highly selective towards the production of monoaldehyde. This could indicate that the interaction between the organic molecule and the electrode surface involves only one adsorption site per molecule.