Iron (II) tetrasulphophthalocyanine complex was adsorbed on a 3-n-propylpyridinium chloride functionalized silica gel surface by means an ion exchange reaction. The amount of the complex bonded to the substrate surface, by electrostatic interaction, is 25 mu mol g(-1) and the specific surface area S-BET = 320 m(2) g(-1). A carbon paste electrode made with the material call electrocatalytically reduce dissolved oxygen to water at a potential Ep(c) = - 140 mV in 0.5 M KCl solution. The plot of the cathodic current against dissolved oxygen concentrations between 0.65 and 14.4 mg dm(-3) showed a linear correlation at 298 K and pH 5. The electrode presented a reproducible response and chemically it was stable under various oxidation-reduction cycles.