Hydroxyl terminated poly(fumaric acid-co-diethylene glycol), poly(FA-co-DEG) was prepared by melt polycondensation. The resultant unsaturated aliphatic polyester was characterized by Fourier transform infrared (FTIR) spectroscopy, hydroxyl value, acid value, and intrinsic viscosity. Its enzymatic degradation and crosslinking behavior as well as the effect of crosslinking degree on enzymatic degradation were also investigated. The crosslinking degree and reduction of carbon-carbon double bonds revealed excellent self-crosslinking nature of poly(FA-co-DEG) at high temperature. The results of enzymatic degradation showed that poly(FA-co-DEG) has excellent biodegradability and that the biodegradation can be controlled by the crosslinking degree. Polyurethane was prepared by the reaction of poly(FA-co-DEG), 2,4-toluene diisocyanate (TDI), and 1,4-butanediol (BD). It was found that the biodegradation of the obtained polyurethane was slower than that of the original unsaturated aliphatic polyester poly(FA-co-DEG). The peeling strength of the polyurethane was very high, supporting better adhesion property with enhanced crosslinking. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 2477-2484, 2011