A series of biomedical polyurethane elastomers (PURs) based on poly(ester-carbonate)s (PECs) and polycarbonates (PCs) were synthesized and spectrally characterized fully. PEC or PC diols were synthesized by the ring-opening polymerization of e-caprolactone, trimethylene carbonate, and neopentyl carbonate catalyzed by lipase from Candida antarctica. PURs were prepared by free-metal method from PEC or PC diols and 4,4'-methylenebis(phenyl isocyanate), with 1,4-butanediol as a chain extender. The physical and mechanical properties as well as hydrolytic stability of the obtained PURs were determined. The toxicity of the received polymers was evaluated using bacterial luminescence test and two protozoans assays. The presented preliminary studies suggest that PEC or PC diols prepared in this way might be applied for the synthesis of biomedical PURs with improved hydrolytic stability. (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012