It is shown theoretically that in continuous electrochromatography the use of an ion‐exchange resin can lead to improved separations. This is because a stationary phase capable of highly selective sorption is provided, within which ions are immobilized with respect to eluant flow but not with respect to current flow. In a system of this kind, in contrast with systems employing conventional supporting media, synergy arises between electrophoresis and chromatography. Even if the ions undergoing separation do not differ greatly in their affinities for the resin, certain advantages result from its presence, particularly when the eluant contains a complexing agent.