The aim of the work is studying the plasticization process of semi-finished chrome tanning from hides of cattle for the production of elastic leather materials. The process of influence of biologically catalytic modifiers on the elastic properties of the leather semi-finished chrome tiling is investigated. The technological parameters of the process of plasticization-filling of leather semi-finished products are determined. The developed plasticisation process of leather semi-finished products using biocatalytic modifier 3 and aerosol A-300 provides the formation of natural leather materials with high elastic-plastic properties while saving chemical materials by 20–25 %. The resulting full-fledged leather material according to the complex of properties meets the requirements for elastic leather materials for garments according to DSTU 3115-95, the interstate standard for leather for the top of shoes "GOST 939-88" and the requirements of the international standard of quality management systems "ISO 9001:2008". Thus, the technology of plasticization-filling of leather semi-finished product was developed, which allows to increase the yield of leather material to 6.7 % compared with the existing technology.