A physicochemical study was made on solutions of a number of lithium salts in diethyl carbonate (DEC) within -20+60°C by means of isothermal saturation, densimetry, and conductometry. The solid phase composition in saturated solutions for LiBF4, LiPF6, and LiCIO4 in DEC were determined. The solubility of the crystal solvates LiBF4·DEC and LiPF6·2DEC increases with temperature while the temperature dependence of the LiCIO4·2DEC goes through an extremum.