Nickel(II) bis(triphenylphosphine)halides [NiX2(PPh3)(2); X = Cl, Br] were employed for possible living radical polymerization of methyl methacrylate (MMA) in conjunction with an organic halide as an initiator [R-X : CCl4, CCl3Br, and (CH3)(2)CBrCO2C2H5] in the presence of Al(OiPr)(3) in benzene at 80 degrees C. The bromide-based initiating system [CCl3Br/NiBr2(PPh3)(2)] gave living polymers with narrow molecular weight distributions, whereas the chloride-based system [CCl4/NiCl2(PPh3)(2)] led to bimodal molecular weight distributions. The systems involving chloride and bromide [CCl4/NiBr3(PPh3)(2) and CCl3-Br/NiCl2(PPh3)(2)] failed to induce living polymerizations. The polymers obtained with (CH3)(2)CBrCO2C2H5/ NiBr2(PPh3)(2) were also living and possessed one initiator moiety at the alpha-end per polymer chain, which indicates the polymerization proceeds via the activation of the C-Br terminal by the nickel(II) bromide complex.