The graft copolymerization of N-vinylpyrrolidone (VP) onto gelatin in aqueous medium, with alpha,alpha’-azobisisobutylonitrile as initiator, has been studied. The effects of various reaction parameters such as temperature, reaction time, as well as the concentrations of initiator, monomer, and gelatin on the percentage of grafting and grafting efficiency were also studied. The chain-transfer constant of isopropanol in this system was calculated. Finally, the grafted samples were analyzed with IR, DSC, TEM, and SEM measurements.