Using cone shaped electrodes, the electrochemical reduction of nitric oxide and oxygen has: been investigated by cyclic voltammetry on an oxygen overstoichiometric (La0.85Sr0.15MnO3+delta) and an oxygen stoichiometric (La0.85Sr0.15CoO3-delta) perovskite over the temperature range 300-500 degrees C. An oxygen ion-conducting 10% gadolinium-doped cerium oxide is used as electrolyte. It is shown that the reduction of nitric oxide proceeds rapidly on La0.85Sr0.15MnO3+delta compared to the oxygen reduction while the oxygen reduction on La0.85Sr0.15CoO3-delta is faster than the nitric oxide reduction.