Curdlan, amylodextrin, and regenerated cellulose fiber were subjected to electromediated oxidation with a 4-acetamido-TEMPO catalyst in a buffer at pH 6.8 without NaClO or NaClO(2). More than 90% of the C6 primary hydroxyls of Curdlan and amylodextrin were converted to sodium carboxylate groups by this method. Molecular mass values of the oxidized products were much higher than those prepared by the TEMPO/NaBr/NaClO system at pH 10. When the regenerate cellulose fiber was treated by the TEMPO electromediated oxidation for 45 h, carboxylate and aldehyde groups of 1.1 and 0.6 mmol/g, respectively, were formed in the oxidized cellulose fiber. The original fibrous and fine surface morphologies were maintained, and nearly no weight losses by the oxidation were observed. Thus, the TEMPO electromediated oxidation is a characteristic and environmentally friendly chemical modification for regenerated cellulose fibers, films, and related forming materials, and ion-exchangeable carboxylate and reactive aldehyde groups can be efficiently introduced into regenerated celluloses.