In electrophoretic membrane contactors, a porous membrane is used to put into contact two flowing liquids between which an electrically driven mass transfer takes place. These processes offer the possibility to scale up electrophoresis as well as to extend the field of application of electrodialysis. This paper deals with the study of the mass transfer mechanisms involved in such electroseparation processes for the separation of binary mixtures. This study is carried out by associating an experimental work and a theoretical approach. The parameters involved in the model are calculated according from the experimental variations of the solvent and solute transfer. From the dependence of these parameters with the operating conditions, the importance of electrostatic interactions with respect to the separation performances is pointed out. Finally, the process performances are studied considering the separation of alpha-lactalbumin and bovine haemoglobin as a case study. (C) 2004 Elsevier B.V. All rights reserved.