In this research mixed matrix heterogeneous cation exchange membranes were prepared by solution casting technique. Ilmenite-co-iron oxide nanoparticle was employed as inorganic filler additive in membrane fabrication. The effect of used additives on membranes properties was studied. Membrane potential, transport number and selectivity were improved by use of FeTiO3/Fe3O4 nanoparticles in membrane matrix. Utilizing FeTiO3-co-Fe3O4 nanoparticles in the casting solution also led to increase in ionic flux obviously. The modified membranes containing FeTiO3-co-Fe3O4 nanoparticles showed higher transport number, selectivity and ionic flux compared to modified membrane containing ilmenite. Results showed that membrane areal electrical resistance was also declined sharply by use of FeTiO3- co-Fe3O4 nanoparticles in membranes matrix. Moreover, modified membrane containing ilmenite showed lower electrical resistance compared to others. Results showed that oxidative stability of membranes was decreased slightly by use of FeTiO3/Fe3O4 nanoparticles in membrane matrix. The results revealed that modified membranes in this study are comparable with that of other commercial ones