The grafting on polyvinyl chloride) by carbanionic deactivation of a living polymer involves two types of reactions: a nucelophilic substitution (SNg) and an elimination (E2). Under the experimental conditions, of our study, we did not observe metallation of the polyvinyl chloride) chain. The influence of different parameters on the ratio E/S of the two reactions has been studied. The substitution is enhanced when the basicity of the carbanion is decreased. Higher temperatures favor the elimination, which might be due to the relative change in the nature of the different ionic species. The appearance of conjugated double bonds, the electroattractive character of which makes the hydrogen atom in theaposition of the C-Cl bond labile, favors autoacceleration of the elimination reaction. The shorter the living chain, higher the yield in substituted product. Steric hindrance of the random coils of PVC and living polymer also plays an important role.