A new class of poly(ester-amide)s was prepared by reacting bis(2-oxazoline)s, carboxylic anhydrides, and diols of different structures. The polymerization proceeds through the formation of a dicarboxy ester by reaction of two anhydride molecules with one diol molecule and subsequent 2-oxazoline ring opening by attack of the dicarboxy ester. The whole process leads to linear poly(ester-amide)s, whose structures were established by carbon and proton NMR analysis. The thermal characteristics of the prepared polymers were studied by differential scanning calorimetry. Transition temperatures were found to increase with an increase in the polymer chain stiffness. Poly(ether-ester-amide)s were also prepared by employing poly(ethylene glycol) as a comonomer, alone, or in a mixture with ethylene glycol, thus obtaining block segmented polymers.