From the electromotive force (e.m.f.) measurements of cells with liquid junction potentials, the standard potentials of a silver electrode were obtained in 5% and 15% (w/w) dioxan-water mixtures at 20, 25, 30 and 35-degrees C, and in 5% (w/w) mannitol-water mixture at 5, 15, 25, and 35-degrees C. The data were used to derive (a) the equation of standard potential for the silver electrode as a function of temperature, (b) the standard thermodynamic quantities for the cell reaction, (c) the standard Gibbs free energy of transfer of Ag+ ion from water to the mixed solvent, and (d) the primary medium effect of the mixed solvent on the Ag+ ion. The results are discussed in terms of ion solvation in these mixed solvents.