Thermodynamic standard Gibbs energies of transfer of alkali metal cations related to Cs+ cation [Delta(t)G degrees(.)*(Cs+) - [Delta(t)G degrees(.)*(M+)] between several mutually saturated solvents of the type water-solvent were calculated from determined extraction exchange constants K-exch degrees(.)*(Cs+/M+). The used liquid-liquid extraction method with radioactive tracing by Cs-137 permits attaining higher precision of the values as compared to the methods used up to now. The data for o-nitrophenyloetyl ether, 1,2-dichloroethane, and 1-octanol were compared with literature sources and recommended absolute values of Delta(t)G degrees(.)*(M+) are reported. For dissociating solvents, the dependences of [Delta(t)G degrees(,)*(Cs+) - [Delta(t)G degrees(,)*(M+)] on Gibbs energy of hydration of an ion, Delta G(hydr)degrees are straight lines either for four cations Cs+, Rb+, K+, and Na+ (nitrosolvents) or for three cations Cs+, Rb+, and K+ (1,2-dichloroethane and 1-octanol). The hydration of Na+ and still more of Li+ in the water-saturated organic phase is apparent from the results. This manifests for high-water-con tent equilibrium 1-octanol even in a reversal of the values [i.e., Delta(t)G degrees(,)*(Li+) being more negative than Delta(t)G degrees(,)*(Na+)], although for Cs+, Rb+, and K+, the general trend is conserved. Water-saturated 1-octanol is thus slightly less basic than water, but the overall selectivity is very low. For one studied nondissociating solvent, dioctyl sebacate, the trend of the dependences of log K-exch degrees(.)*(CsB/M+) on Delta G(hydr)degrees is similar to that of K-exch degrees(.)*(CS+/M+) for polar solvents, but different for different anions B, thus reflecting ion association in the organic phase.