This article describes a facile approach for the synthesis of water-soluble ABC triblock copolymers through a combination of atom transfer radical polymerization (ATRP) and click reactions. The bromine-terminated MPEO-PtBA-Br precursor was first prepared by ATRP, and converted into the azido-terminated precursor MPEO-PtBA-N(3) by a simple nucleophilic substitution. Then, MPEO-PtBA-PzLLys triblock copolymers were synthesized via the click reaction of MPEO-PtBA-N(3) and the propargyl-terminated poly(N(epsilon)-carbobenzoxy-L-lysine)s (PzLLys). The water-soluble MPEO-PAA-PLLys ABC triblock copolymers were obtained from the hydrolysis process. The structures of these block copolymers were characterized by NMR, IR and GPC. (C) 2009 Elsevier Ltd. All rights reserved.