AbstractVinyl chloride has been polymerized by a modified Ziegler‐Natta type catalyst VOCl2· 2THF–Al(i‐Bu)3–THF, and the kinetics of the polymerization reaction have been investigated in some detail. The present kinetic analysis has demonstrated that the generation of active centers is directly proportional to the catalyst concentration, and that their depletion is by a second‐order decay process. Triisobutylaluminum has been found to contribute to the effective removal of active centers through complex