Chitosan is a polysaccharide derived from chitin, which is commonly found in shellfish waste materials. The present work is concerned with the graft copolymerization of 2-hydroxyethylmethacrylate (HEMA) onto chitosan using thiocarbonation-potassium bromate for redox initiation. The combined effects of the principal reaction variables for the grafting reaction were studied systematically. This grafting reaction was studied with respect to percentages of graft yield (%G.Y.), homopolymer (%H.P.), and total conversion (%T.C.). A tentative polymerization mechanism is proposed.