The Gibbs' free energies of transfer of silver(I) ion, Delta(t)G(d)egrees(Ag+), from water to water-dimethyl sulfoxide (W/D) binary mixtures have been used to obtain the distribution of solvated ions, [AgWjDk](+), present over the mole fraction range from 0.05 to 0.95 for dimethyl sulfoxide. Major species were [AgW3D](+), [AgW16D](+), [AgW3D2](+), [AgWD3](+), [AgD6](+), [AgWD9](+), [AgD14](+). The water-rich solvated ions were present only at small dimethyl sulfoxide concentrations.