Dihydridotetrakis(triphenylphosphine)ruthenium(II) [RuH2(PPh3)(4)] induced a fast living radical polymerization of methyl methacrylate (MMA) in conjunction with an organic chloride initiator [R-Cl:CHCl2COPh] in toluene at 30-80 degrees C. Added aluminum compounds such as Al(O-i-Pr)(3) were not needed for the Ru(II)-hydride system unlike the reported RuCl2(PPh3)(3)-based counterpart. The number-average molecular weights of polymers increased in direct proportion to monomer conversion, and the molecular weight distributions were narrow ((M) over bar(w)(M) over bar(n) < 1.2) even at 30 degrees C. The polymers possessed one initiator moiety (COPh) at the alpha-end per one polymer chain. The stereochemistry of the polymers was consistent with that for conventional free radical polymerization in that the fraction of syndiotactic arrangements increases as the reaction temperature is lowered (58% and 67% rr triads at 80 and 30 degrees C, respectively).