A novel biodegradable copolyester poly(epsilon-caprolactone-co-D,L-lactide) with four pendent functional groups was designed and synthesized. The synthetic route includes the following three steps: (1) synthesis of OH-terminated PCLA (PCLA-OH) by the ring-opening copolymerization of epsilon-caprolactone and D, L-lactide; (2) end-group functionalization of PCLA-OH through the esterification with lysine; and (3) synthesis of tetra-amino-terminated PCLA (PCLA-NH2) by removing the protecting groups. The composition, structure, and thermal property of these copolyesters were characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and modulated differential scanning calorimetry. Results revealed that the molecular weight and glass transition temperature of PCLA-NH2 can be tailored by the careful selection of synthesis parameters. Moreover, polyester elastomers based on PCLA-NH2 were synthesized and characterized. These polyester elastomers are stabilized in their rubbery state in room temperature and exhibit tunable physiochemical and mechanical properties. (C) 2013 Society of Plastics Engineers