Due to the presence of an unshared pair of electrons, nitrogen-contain ing unsaturated compounds inhibit the polymerization of olefins on complex catalysts when they are introduced into the reaction system. We established that the preliminary bonding of such monomers as diallylamine, vinylpyridine, acrylonitrile, etc., in complexes with transition metal halogenides (VC14, TIC14), permits their involvement in the co-polymerizatio n with ethylene in the presence of AI(i-C4Hg)2CI (t = 40-60~ solvent: n-heptane, ethylene pressure: 200-600 mm Hg, [A1]/[M] = 5-10; the method of carrying out the eopolymeri= zation has been described [1, 2]. The monomers mentioned above also function as modifiers of the catalytic system here, since systems which contain the monomers listed above, in contrast to unstable binary systems like MC14--A1R2C1 , possess a practically constant activity for 2-3 h after a small induction period (5-20 rain). We isolated VC14 complexes with one, two, and three acrylonitrile molecules, and also a VC14 complex with two diallylamine molecules, and a TiC14 complex with two acrylonitrile molecules, and it was shown that the ethylene polymers obtained in the presence of catalytic systems which were prepared on the basis of these complexes, contain from 0.1 to 0.5% nitrogen (micro Dumas method). The IR spectra also confirm the formation of ethylene copolymers with the nitrogen-contain ing monomers: there is a band due to the valence vibrations of the C-~N at 2245 cm -1 in the IR spectrum of the ethylene copoiymer with acrylonitrile, and also a band at 1640 cm-1 evidently associated with vibrations of the C=C and C-~N groups. An investigation of the spectra showed that these bands cannot be li~k6d with either an impurity in the polymer from some undeeomposed VC14 complex with aerylonitrfle or with an impurity from an aerylonitrile homopolymer. A band due to the N--H valence vibrations at 3350 ern -1 is present in the IR spectrum of the ethylene-diallyl amine eopolymer.