Poly(ethyl methacrylate) has been grafted onto partially hydrolysed starch (84.04% conversion) by using ceric ion redox initiator in an aqueous medium at 29degreesC. The extent of graft polymer formation was measured in terms of conversion of monomer to polymer, graft level, molecular weight of grafted polymer chains and grafting frequency as a function of ceric ion concentration. It was found that an eight-fold increase in ceric ion concentration was accompanied by marked changes (or about three-fold in graft level, six-fold in molecular weight or grafted polymer chains and four-fold in grafting frequency) in the values of the measured grafting parameters. A ten-fold increase in the polymeric substrate to dispersion medium ratio was found to increase the extent of graft polymer formation onto partially hydrolysed starch.