Particle size, mineral, and chemical composition of oozy mud have been studied. It was established that the muds of different lakes vary in mineral composition of salt components, which may correspond to different identified mineral salt types: carbonate, sulfate or chloride. It has been shown that the Fe-VMn-Pb-Y-Mn association in the mud of the lakes in the south part of the Kerch Peninsula is governed by the composition of weathered iron ores, which served as a source of the drift of sedimentary material into the lake basin. Elevated concentrations of Rb, Cu, Zn, Mo, Ni, U in the mud of the Dead Sea are caused, most likely, by unloading of deep metalliferous calcium-chloride brines, supplying the Dead Sea. In general, the muds of the Crimean lakes are characterized by a higher sulfur percentage, compared to the Dead Sea. Size distribution of the oozy mud is determined by the distance from the shore, beach sediments particle size distribution, protection of mud by overlying layer of brine, position in the section, influence of anthropogenic factors. Refs 6. Figs 9. Table 1.