Novel biodegradable network polyesters were prepared from multifunctional aromatic carboxylic acids [trimesic acid (Y), pyromellic acid (X), and mellic acid (Y-M)] and poly(is an element of-caprolactone) (PCL) diols with molecular weights of 530, 1250, and 2000. Prepolymers prepared by a melt polycondensation method were cast from dimethylformamide solutions and postpolymerized at 220 degreesC for various times to form a network. The resultant films were transparent, flexible, and insoluble in organic solvents. The network polyesters obtained were characterized by infrared absorption spectra, wide-angle X-ray diffraction analysis, density measurements, differential scanning calorimetry, thermomechanical analysis, and tensile testing. Some network polyester films, including YPCL1250, XPCL1250, and YMPCL2000, showed elastomeric properties with high ultimate elongation and low tensile modulus. The enzymatic degradation was measured by the weight loss of the network polyester films in a buffer solution with Rhizopus delemar lipase at 37 degreesC. The degree and rate of degradation increased with the increasing molecular weight of the PCL diols, but they decreased in the order of YPCL > XPCL > YMPCL because of the increase in the crosslinking densities of the network films. The degraded products after enzymatic degradation showed that the ester linkage of the PCL component and the aromatic ester linkage between Y and PCL diols were hydrolyzed.