Abstract Many scientists in this country and abroad are engaged in the study of polymerization of various compounds in the solid phase, as one of the methods of producing polymers with valuable new properties. The reaction of polycondensation of bifunctional compounds in the solid state, which is one of the main methods of synthesizing highly fusible polymers, has hardly been investigated. The investigations in this field are restricted to a small number of studies of polyamidation [1, 8] and polyesterification in the solid phase [10, 11]. Copolycondensation of bifunctional compounds with various functional groups was only studied in the liquid phase, in the melt or in solution. Several highly fusible copolymers which are obtained by copolycondensation in solid phase [12,–14] are mentioned in the patent literature of recent years. It appeared to be of interest therefore to study the reaction of copolycondensation of bifunctional monomers containing amine, carboxyl and hydroxyl groups in the solid state. This paper is devoted to the study of the kinetics of the reaction of copolycondensation of two α,ω-aminoacids having a general formula H 2(CH 2) n COOH with low-molecular weight products of condensation of dimethyl terephthalate with ethylene glycol.