The polymerization behaviour of methyl methacrylate (MMA) in p-xylene in the presence of CuCl/L [L = 1,10-phenanthroline (phen) or 4,7-diphenyl-1,10-phenanthroline (DPP)] and tetrachlorocarbon has been studied. For the CCl4/CuCl/phen/MMA/p-xylene system. the linear relationship between the number-average molecular weight of the resulting poly(methyl methacrylate) (PMMA) and MMA conversion, as well as between In[M](0)/[M] and time, demonstrate the ＇living＇ nature of this system. When phen is replaced by DPP the polymerization becomes slower, but the molecular weight and molecular weight distribution are better controlled. The stereochemistry of PMMA synthesized in the CCl4/CuCl/DPP/MMA/p-xylene system indicates that the MMA monomer adds to the living polymer chain end in an atactic fashion.