This paper presents the results of an investigation of the properties of a modified platinum electrode with meso-tetraphenylporphyrin iron(III) complex immobilized in Nafion film and its catalytic activity in the electrochemical oxidation of selected hydroquinone and catechol derivatives. The redox activity of iron complexes of porphyrins was characterized in aqueous solutions of perchloric acid by means of cyclic voltammetry and differential pulse voltammetry. Both the increase in the anodic peak currents of the investigated compounds during oxidation on the platinum electrode modified with meso-tetraphenylporphyrin iron(III) complex immobilized in Nafion film (FeTPhP/Nafion/Pt) and the considerable decrease in the cathodic peak currents related to the porphyrine complexes reduction point to mediatory activity. The increase in the oxidation currents observed during the preparative electrolyses indicates that the modified platinum electrode, FeTPhP/Nafion/Pt, exhibits catalytic properties. The preparative electrooxidation of the investigated 1,2- and 1,4-hydroquinone derivatives showed that over 90% conversion of the substrate occurs in the shortest time on platinum modified with iron complex of porphyrin immobilized in Nafion film.