The polymerization of 4-methylstyrene with the (trimethyl)pentamethylcyclopentadienyltitanium (Cp*TiMe3)/tris(pentafluorophenyl)borane (B(C6F5)(3))/trioctylaluminium (AlOct(3)) catalytic system at -20 degrees C was carried out. The number-average molecular weight ((M) over bar(n)) of the polymers increased linearly with increasing monomer conversion. The propagating chain ends were successfully reacted with tert-butyl isocyanate, and the (M) over bar(n) of the polymer determined by H-1 NMR was in good agreement with the (M) over bar(n), determined by GPC measurement. It is concluded that this catalytic system promoted the syndiospecific living polymerization of 4-methylstyrene.