Controlled release of glucose as a model compound through modified chitosan membranes was studied. The chitosan membranes were modified by graft copolymerization of 2-hydroxyethylmethacrylate (HEMA) onto chitosan films using Co-60 gamma-ray irradiation. The release characteristics of glucose were studied as a function of degree of grafting. The permeability coefficient of glucose through grafted membranes was found to be in the order 10(-6)-10(-7) cm(2)/s. The effect of thickness of membranes on the permeability was also determined. Chitosan membranes showed a negligible boundary layer effect. The release of,glucose was found to be pH dependent.