Chemical derivatization of pullulan, such as oxidation, etherification, esterification, and hydrogenation have been reported since many years. Particularly, the oxidation of pullulan to carboxypullulan is an important direction to functionalization the hydroxyl groups in the maltotriose unit of pullulan. The introduction of carboxylic groups in the pullulan backbone provide anionic polymers, able to interact more effectively with other charged compounds. Thus, pullulan can be readily oxidized at primary hydroxyl groups to the carboxylic moiety by using free nitroxyl radicals, such as TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) and a primary oxidant, like sodium hypochlorite (NaOCl). In this process the nitrosonium salt is the key species resulting from the conversion of the nitroxyl radical in the presence of NaBr/NaOCl. According to the current trends in catalysis, attempts have been made to immobilize N-hydroxyphthalimide (NHPI) into solid support in order to obtain easy separable and reusable catalyst. In this work, we would like to propose a convenient route for the selective conversion of the primary OH groups in the water soluble pullulan, using a new catalytic polymer-supported N-hydroxyphthalimide (NHPI) immobilized on polystyrene via amide or ester bonds. All reactions were carried out at room temperature, atmospheric pressure and pH=10. The characterization of the catalysts and oxidized products has been done using NMR and FTIR methods. The analyses of the oxidized pullulans reveals that in all samples, the primary alcohol groups were selectively oxidized into carboxyl groups. The possibility of recovery and recycling of the polymer-supported NHPI catalyst was tested for up to four cycles, since the morphological analyses performed on the catalysts using SEM, revealed no significant changes.