The polymerization of methyl methacrylate (MMA) initiated by α‐picolinium‐p‐chlorophenacylide in CCl4 at 30, 35, and 40°C for four h was investigated dilatometrically. The orders of reaction with respect to the concentrations of ylide and MMA are 0.22 ± 0.01 and 1.0, respectively. The overall energy of activation and an average value of k p2/kt are 21.0 kJmol−1 and 0.37 ± 10−2, respectively. The results are explained in terms of radical mode of polymerization with initiator dependent transfer besides bimolecular termination.