The concentration dependences of the electrolyte sorption, specific electric conductivity, and diffusion permeability of MK-40 and Nafion-117 cation-Ion-exchange membranes in NaCl solutions have been obtained experimentally. Both the membranes contain macropores. The heterogeneous MK-40 membrane contains pores with a size of up to 1 mu m between the particles of the ion Ion-exchange resin and polyethylene. The homogeneous Nafion-117 membrane has been subjected to a special thermal pretreatment which results in the formation of macropores. It has been shown for the first time that these experimentally found relationships can be quantitatively described using one set of structural and kinetic parameters of the microheterogeneous model.