The polar solvents, N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), and acetonitrile (CH3CN) were used as ligands for iron(III)-mediated activators generated by electron transfer atom transfer radical polymerizations (AGET ATRPs) of methyl methacrylate (MMA) with various initiators and reducing agents. Polymerizations were conducted with a molar ratio of [MMA]0/[initiator]0/[FeBr3]0/[reducing agent]0 = 100:1:1:0.5 and a volume ratio of MMA/solvent = 2:1 at 60 °C to investigate the effects of initiator, solvent and reducing agent, and most of the systems showed the typical features of “living”/controlled radical polymerization. In order to get a deeper understanding of the mechanism, the amount of the reducing agent was changed to study the polymerization behavior. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1020–1027