Segmented polyesteramides have been synthesized from N,N¿-bis(p-carbomethoxybenzoy)butanediamine as crystalline segments and mixtures of poly(tetramethylene oxide) (mol. wt. 1000) and 1,5-pentanediol as soft segments. The polymerization was carried out in the melt at 250°C for 1 h while vacuum was applied. The melting behaviour of the copolymers was studied by differential scanning calorimetry. The mechanical properties were investigated on injection moulded bars, using dynamic mechanical analysis. It was found that the copolymers with more than 50% molar ratio pentanediol showed two glass transition temperatures and two melting temperatures. The glass transition temperatures were not affected by the composition. The melting temperatures increased with pentanediol content. The pentanediol seems in part to be present as adjacent re-entry groups. The under-cooling for these copolymers was very small, which means that these segmented copolymers crystallize very fast.