The present paper describes the covalent immobilization of cobalt phthalocyanine "MEROX catalyst" to polystyrene resin via sulfonamide linkage and its catalytic activity for the oxidation of mercaptans to disulfides using molecular oxygen as an oxidant under alkaline conditions. Polymer-supported cobalt phthalocyanine, wherein the catalyst is chemically bounded to the support which prevents the leaching of the catalystiligand, can readily be recovered from the reaction mixture and reused for several runs without significant decrease in catalytic activity.