In order to initiate a comprehensive study of graft copolymerization of vinyl monomers onto soluble protein-gelatin, we have studied grafting of ethyl acrylate (EA) and methyl methacrylate (MMA) onto gelatin using eerie ammonium nitrate (CAN) and eerie ammonium sulfate (CAS) as the redox initiator in an aqueous medium. A small amount of mineral acid (HNO3with CAN and H2SO4 with CAS) was found to catalyze the graft copolymerization. Graft copolymerization reactions were carried out at different temperatures. Maximum grafting occurred at 65°C both with EA and MMA. Percentage grafting has been determined as function of 1) concentration of monomer (EA and MMA), 2) concentration of initiator (CAN and CAS), 3) concentration of acid (HNO3 and H2SO4), 4) time, and 5) temperature.