[en] The concentration of water in purified and BaO-dried α-methylstyrene was found to be 1.1 x 10^-4M. The radiation-induced bulk polymerization of the α-methylstyrene thus prepared was studied in the temperature range of -20⁰ to 35⁰C. The polymerization rate varied as the 0.55 power of the dose rate. The theoretical molecular weights and molecular weight distribution were calculated from a proposed kinetic scheme and these values were then compared with those found experimentally. The agreement between these two was reasonably close, and therefore it was concluded that, from the molecular weight distribution point of view, the proposed kinetic scheme for the cationic polmerization of α-methylstyrene is an acceptable one. The rate constant for chain transfer to monomer k/sub f/ changed with temperature and was found to be responsible for the decrease in the molecular weight of the polymer with increase in temperature. k/sub f/ and k/sub p/ at 20⁰C were found to be 0.95 x 10⁴ l./mole-sec and 0.99 x 10⁶ l./mole-sec, respectively