A new poly (amide ester)-ester copolymer was synthesized by reacting two oligomers. namely, oligo (amide ester) and oligo ester. Depending on the molar ratio of the two oligomers, a behavioural pattern of elastomeric to elastoplastic material was observed. D.s.c. studies revealed two glass transition temperatures: one at - 40 to - 50-degrees-C and another at 40 to 50-degrees-C, showing the presence of two different segments in the polymer backbone. Electron microscopic studies could not distinguish and differentiate the phase separation behaviour of the segments in the polymer. Mechanical studies showed that the polymer has a tensile strength at break of 6-20 MPa with an elongation as high as 160%.