In order to improve upon certain properties of gelatin graft, copolymerization of acrylonitrile (AN) and methacrylonitrile (MAN) onto gelatin has been studied in aqueous medium using gamma rays as a source of initiation. Optimum conditions for affording maximum percentage of grafting have been evaluated as a function of various reaction parameters. The grafted polyacrylonitrile (PAN) was isolated from the graft copolymer by acid hydrolysis, and the average molecular weight (M(upsilon)) of the isolated polymer has been determined viscometrically. The graft copolymers were characterized by IR spectroscopic methods and thermogravimetric analysis (TGA). Acrylonitrile was found to be more reactive than methacrylonitrile toward graft copolymerization.