This article deals with the issues of determining the mineralogical composition of soil samples in the city of Navoi and the Karmaninsky district (the settlement of Khazora, 24 km from the city) and identifying the degree of salinization of these old irrigated soils in the region. To determine the mineralogical composition of soil soils, the X-ray diffraction method of research was used, and to determine the functional groups of carbon, sulfur, and chlorine, IR spectrometric analysis of samples was used. The studies carried out made it possible to establish a carbonate type of salinity for the city of Navoi, and for the Karmaninsky district, the dominance was noted first of carbonate - 45.4%, then sulfate 28.8%, and only lastly did the third type of salinity appear, represented by chloride - 0.8%, found on the surface layer of the soil (0-0, mm).