The comparative study of electrochemical behaviour of 5-(pyrid-3-yl)-10,15,20-tri-phenylporphyrin (H2(3-Py)triPhP) and its Co-, (Py)Co-complexes was carried out by the method of cyclic voltammetry in an aqueous alkaline solution. The influence of the nature of the functional substituents and the metal, as well as additional extraligand on the character of cyclic I,E- curves, values of the redox potentials and the electrocatalytic activity of the compounds in the reaction of ionization of molecular oxygen was established.