To make starch /polycaprolactone (PCL) blend with high miscibility, starch was chlorinated (starch-Cl) by using methanesulfonylchloride (CH3SO2Cl) in dimethylformamide (DMF) prior to blending. Starch-ClI/PCL blends were prepared by the mixing between starch-Cl and PCL solutions under various conditions. To study the change of structure, thermal and physical characteristics of starch-Cl/PCL blend, FTIR, DSC, SEM, and solvent resistance were measured. By blending starch-Cl and PCL, a chemical reaction occurred partially in blend (FTIR result); thereby, the miscibility (DSC and SEM results) and solvent resistance were increased. (C) 2004 Wiley Periodicals, Inc.