This article reports the synthesis and the properties of novel thermoplastic elastomers of A-B-A type triblock copolymer structure, where the hard segment A is poly(l-lactide) (PLLA) and the soft segment B is poly(epsilon-caprolactone-stat-d,l-lactide) (P(CL-stat-DLLA)). The P(CL-stat-DLLA) block with DLLA content of 30 mol % was applied because of its amorphous nature and low glass transition temperature (T-g=approximately -40 degrees C). Successive polymerization of l-lactide afforded PLLA-block-P(CL-stat-DLLA)-block-PLLAs, which exhibited melting temperature (T-m=approximately 150 degrees C) for the crystalline PLLA segments and still low T-g (approximately -30 degrees C) of the soft segments. The triblock copolymers showed very high elongation at break up to approximately 2800% and elastic properties. The corresponding d-triblock copolymers, PDLA-block-P(CL-stat-DLLA)-block-PDLAs (PDLA=poly(d-lactide)) were also prepared with the same procedure using d-lactide in place of l-lactide. When the PLLA-block-P(CL-stat-DLLA)-block-PLLA was blended with PDLA-block-P(CL-stat-DLLA)-block-PDLA, stereocomplex crystals were formed to enhance their T-m as well as tensile properties. (c) 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 489-495