Abstract Polycondensation of diethyl 2,3,4,5‐tetrahydroxyadipate with various diamines was carried out in solutions under mild conditions. The polycondensation reaction occurred rapidly even at room temperature in polar solvents such as alcohols, and in aqueous solution a cyclic product was obtained instead of linear polymers although the reaction with diamines was completed within several minutes. Polymers obtained from diethyl 2,3,4,5‐tetrahydroxyadipate were a linear polyamide having pendant hydroxyl groups, which decomposed on heating at around 200°C. A solid‐phase polycondensation of the precursor polyamide yielded a high molecular weight polyamide.