Abstract: The packing and even the excessive packaging of products for human consumption is a current practice in the industrialized countries. As this packaging is made primarily of non-biodegradable polymers, they currently cause environmental problems. These environmental problems are found not only in industrialized countries but also in developing countries. This situation supported the development of various films, more ecological, starting from biodegradable elements containing polysaccharides, proteins and/or lipids. We developed a biodegradable protein film from a casein salt. Of dairy origin, casein is abundant and could even be recovered from unsold milk. The process of polymerization is induced by gamma irradiation. Indeed, the interaction of hydroxyl radicals with tyrosins present in protein creates a covalent bond (bityrosine). The addition of a plasticizing agent is essential in order to produce a more flexible and less friable film. The presence of glycerol does not inhibit the formation of bityrosine.