The oxidation of nitrite on a vitreous carbon electrode modified with different surface concentrations of cobalt phthalocyanine (CoPc) was investigated using cyclic voltammetry and rotating disk electrode techniques. The voltammetric curves show well-defined anodic peak. which is indicative of the electrocatalytic oxidation of nitrite. The activity of the modified electrodes does not increase with the amount of CoPc adsorbed on the electrode in a wide range of surface coverages and the order of the electro-oxidation reaction is one in nitrite. Tafel plots obtained from rotating disk measurements give two linear regions of slopes of 0.071 and 0.14 V/decade, respectively. This was discussed in terms of a catalytic process and a mechanism is proposed.