The reversible addition-fragmentation chain transfer (RAFT) polymerization technique has been employed to synthesize linear alpha,omega -telechelic polymers with either hydroxyl or carboxyl end groups. Methyl methaerylate, butyl methacrylate, and butyl acrylate were polymerized with RAFT polymerization. The polymerizations exhibited the usual characteristics of living processes. Telechelic polymethacrylates were obtained from a hydroxyl monofunctional RAFT polymer with a two-step chain-end modification procedure of the dithioester end group. The procedure consisted of an aminolysis followed by a Michael addition on the resulting thiol. The different steps of the procedure were followed by detailed analysis. It was found that this route was always accompanied by side reactions, resulting in disulfides and hydrogen-terminated polymer chains as side products next to the hydroxyl-terminated telechelic polymers. Telechelic poly(butyl acrylates) with carboxyl end groups were produced in a single step procedure with difunctional trithiocarbonates as RAFT agents. The high yield in terms of end group functionality was confirmed by a new critical-liquid-chromatography method, in which the polymers were separated based on acid-functionality and by mass spectrometry analysis. (C) 2005 Wiley Periodicals, Inc.