Two series of novel oligo(ester amide)s based on sebacic acid/1,6-hexanediamine/epsilon-caprolactone and octadecanedioic acid/1,6-hexanediamine/epsilon-caprolactone were synthesized. The determination of the molecular weights with both gel permeation chromatography and H-1 nuclear magnetic resonance (n.m.r.) showed that they vary from 1000 to 6000. Differential scanning calorimetry and thermogravimetric analysis were employed for determining glass transitions, melting points, heats of melting and decomposition temperatures of the oligo(ester amide)s. Fourier-transform infra-red and H-1-C-13 n.m.r. spectra were taken to confirm the composition of the novel oligo(ester amide)s. The test of enzymatic hydrolysis was employed to assess the potential biodegradability of these oligomers.