Electrochemical properties of ion-exchange resins such as specific eonductances, ionic mobilities in the resins, and potentials across resinous membranes have been measured recently. A review of these measurements and their correlation to the general thermodynamic treatment of ion-exchange resins is presented. Applications such as the use of resinous membranes as ionic sieves, electrolytic regeneration of ion-exchange resins, and the use of ion-exchange resins as media for eleetrophorefie separations are discussed.