alpha,omega-Di(iodo)poly(vinyl chloride)s with number-average molecular weights (M-n's) of 2100-29,800 and weight-average molecular weight/number-average molecular weight (M-w/M-n) ratios of 1.66-2.16 were synthesized by the single-electron-transfer/degenerative-chain-transfer mediated living radical polymerization of vinyl chloride initiated with CHI3 and catalyzed by Na2S2O4. These alpha,omega-di(iodo)poly(vinyl chloride)s were used as initiators for the metal-catalyzed living radical block copolymerization of methyl methacrylate mediated by CuCl/2,2 '-bipyridine. Poly(methyl methaerylate)-b-poly(vinyl chloride)-b-poly(methyl methacrylate) block copolymers with M. values of 36,500-95,700 and M-w/M-n values lower than 1.20 were synthesized by this novel and general synthetic method. (c) 2005 Wiley Periodicals, Inc.