Xylan isolated from beechwood was alkylated with p-carboxybenzyl bromide in aqueous alkali. The alkylation by varying stochiometry and reaction temperature yielded carboxybenzylated xylan derivatives with a degree of substitution which ranged from 0.05 to 0.25. The reaction products were characterized by elementary analysis and FTIR and UV spectroscopy. As tested by HPGPC, no degradation of the xylan chains resulted up to a reaction temperature of 40 degrees C. The derivatives show moderate surface activity.