Graft copolymer of polypropylene and butadiene-acrylonitrile random copolymer was prepared by reactive polymer blending in a melt without solvents. The process was performed by preliminary grafting of maleic anhydride groups to polypropylene and of isocyanate groups to butadiene-acrylonitrile copolymer, followed by blending of the modified polymers. The chemical reactions occurring in the process and the fraction composition of the copolymer were studied.