Polycaprolactone-graft-glycidyl methacrylate (PCL-g-GMA) copolymer was prepared by grafting GMA onto PCL in a batch mixer using benzoyl peroxide as an initiator. The graft content was determined with the H-1-NMR spectroscopy by calculating the relative area of the characteristic peaks of PCL and GMA. The graft content increased with the increase of GMA concentration. The methine proton peak appearing at 3.65 ppm in H-1-NMR spectra could be assigned as a grafting site of GMA by the correlation spectra (H,H-COSY). Molecular weight determination was also carried out for the pure and grafted polymers using gel permeation chromatography to determine chain scission reaction. The detailed grafting reaction mechanism was discussed based on the results of GPC and NMR measurements. (C) 2001 Published by Elsevier Science Ltd.