The oxidation of piperidine in an aqueous sodium sulphate solution has been studied, by a variety of electrochemical methods, on platinum and mercury. The diffusion coefficient of piperidine was evaluated. The reaction involves a transfer of two electrons, with the participation of two hydroxyl ions per molecule of piperidine oxidized. The mechanism of the reaction is first order and controlled by mass transport and the kinetics of the surface process on platinum. Evidence is presented in support of the proposal that piperidine-N-oxide and not pyridine, as suggested by earlier workers, is the most probable product of the electrochemical oxidation.