In the polymerization of α‐methylstyrene (α‐MeSt) in dichloromethane in the temperature interval between −60 and −20°C the polymer yield decreased with increasing temperature depending on the initiating system used (I‐IV) in the series II > I > IV > III, where I was a freshly prepared solution of 2,5‐dichloro‐2,5‐dimethylhexane (DDH) with BCl3 in dichloromethane, was the same solution as in the preceding case, but stored at room temperature one month and then used, III was a freshly prepared BCl3 solution in dichloromethane, and IV was the initiation system “H2O”/BCl3. The polymer samples synthesized at ≤ −30°C had a bimodal molecular weight distribution (MWD), which was attributed to the different participation of ionic pairs and free ions in the propagation reaction. The stereoregularity of the polymer observed (ca. 85% syndiotactic and ca. 15% heterotactic triads) determined from the 1H‐NMR spectra was not affected by the difference in the initiation system. MWD of the polymer samples was investigated by the GPC method