A new graft copolymer, poly(2-hydroxyethyl methacrylate-co-styrene) -graft-poly(epsilon-caprolactone), was prepared by combination of reversible addition-fragmentation chain transfer polymerization (RAFT) with coordination-insertion ring-opening polymerization (ROP). The copolymerization of styrene (St) and 2-hydroxyethyl methacrylate (HEMA) was carried out at 60 degreesC in the presence of 2-phenylprop-2-yl dithiobenzoate (PPDTB) using AIBN as initiator. The molecular weight of poly (2-hydroxyethyl methacrylate-co-styrene) [poly(HEMA-co-St)] increased with the monomer conversion, and the molecular weight distribution was in the range of 1.09 similar to 1.39. The ring-opening polymerization (ROP) Of E-caprolactone was then initiated by the hydroxyl groups of the poly(HEMA-co-St) precursors in the presence of stannous octoate (Sn(Oct)(2)). GPC and H-1-NMR data demonstrated the polymerization courses are under control, and nearly all hydroxyl groups took part in the initiation. The efficiency of grafting was very high. (C) 2004 Wiley Periodicals, Inc.