The preferential solvation of the silver salts silver(I) bromate, iodate, sulfate, and oxalate in the binary solvent mixtures of water and N-methyl-2-pyrrolidinone has been studied by solubility and solvent transport number measurements. The Gibbs transfer energies of the salts from water to water + N-methyl-2-pyrrolidinone mixtures, calculated from solubility data, were split into their ionic values by using the transfer energies of silver ion determined on the basis of the negligible liquid junction potential method. These data have also been compared with those obtained on the basis of the tetraphenylarsonium tetraphenylborate method. Solvent transport numbers (Δ′) of N-methyl-2-pyrrolidinone were determined for all the salts by employing a concentration cell with transference as suggested by Wagner. The results have been interpreted in terms of heteroselective solvation of all the salts, with silver ion being selectively solvated by N-methyl-2-pyrrolidinone and anions by water. © 1995, American Chemical Society. All rights reserved.