Ferrocene (Fe(CP)(2)) was added to a thermal initiation of reversible addition-fragmentation chain transfer (RAFT) polymerization of methyl methacrylate (MMA) with 2-cyanoprop-2-yl 1-dithionaphthalate (CPDN) as the RAFT agent at 115 degrees C. It was found that the polymerization was greatly promoted after the addition of Fe(CP)(2) while retaining the characteristics of a typical RAFT polymerization. It was proposed that the formation of a redox initiation system, in which the poly (methyl methacrylate) peroxide (PMMAP) generated in situ as the oxidizer and Fe(CP)(2) as the reducer, was possibly the reason for the interesting polymerization phenomenon. Such a redox initiation mechanism was further validated with ascorbic acid (VC) as the reducer instead of Fe(CP)(2). (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3607-3615, 2009