The reaction kinetics and characterization of the reaction products of the modification of the vinyl chloride oligomer containing CCl3end groups by n-butyl methacrylate in the presence of copper (II) ephedrinate was studied. The reaction product contains three high molecular weight components: modi- fied poly(vinyl chloride) (copolymer), unchanged vinyl chloride oligomer, and poly(n-butyl methacrylate) homopolymer. The extent of the modification process depends on the molar ratio between the concentration of the halogen-containing groups utilizable for the reaction with metal chelate and on the concentration of metal chelate. If there is a molar excess of chelate compared with the molar concentration of CCl3end groups in vinyl chloride oligomer, then other halogen-containing groups besides CCl3end groups of vinyl chloride oligomer are used in the formation of modified poly(viny1 chloride). This enables incorporation of more than two poly(n-butyl methacrylate) sequences into the poly(vinyl chloride) chain.