The present invention is directed to a poly(ethylene glycol)-grafted aliphatic polyester represented by Formula 1: ##STR00001## wherein X is an aliphatic ester, R is hydrogen or C.sub.1-5 alkyl, Z is the binding moiety of an initiator or a chain transfer agent, m/l is from 0.1 to 50, n is from 2 to 50, w is 1 or greater, and y is from 1 to 200. Further disclosed is a method for preparing the poly(ethylene glycol)-grafted aliphatic polyester of the present invention.