It has been established that the relations of the two-phase system model are applicable for describing the thermal properties of solids with disordered and crystalline structures. It is shown that the model adequately describes the curves of isochronous and isothermal crys-tallization of amorphous alloys and thermal changes in the volume of their samples. It is also suitable for calculating the heat capacities and thermal expansion coefficients of sub-stances that are diverse in their physical nature. Keywords: two-phase system, thermal expansion coefficient, heat capacity, amorphous alloys, com-plex oxides.