Well-defined norbornene-lactone-functionalized polymers were synthesized by atom transfer radical polymerization (ATRP) of 5-methacryloxy-6-hydroxynorbornene-2-carboxylic-6-lactone (MNL) and 5-acryloxy-6-hydroxynorbornene-2-carboxylic-6-lactone (ANL) monomers. The ATRP of MNL initiated by ethyl 2-bromopropionate (EBrP), in both N,N-dimethylformamide (DMF) and o-dichlorobenzene (ODCB) solvents was successfully carried out in the presence of CuCl/CuBr and N,N,N'',N'',N''-pentamethyltriethylenetetramine (PMDETA) at 70 A degrees C. The CuCl/ODCB catalyst system gave rise to a lower M (w)/M (n) (a parts per thousand broken vertical bar 1.20) than CuBr/DMF catalyst system. The ATRP of ANL was feasible in the presence of CuBr and PMDETA at 70 A degrees C but showed lower reactivity than MNL. The resulting polymers were characterized by means of gel permeation chromatography (GPC) and H-1 NMR spectroscopy.