New ceramic ultrafiltration membranes with a pore size diameter in the range of 6 nm have been prepared by sol gel route using TiO2 and ZnAl2O4 mixed sols. The main characteristics of the membranes an given and their filtering properties discussed by taking into account of the electrophoretic behavior of powder suspension elaborated with the different sols used for the membrane preparation. As for other membrane materials, the salt rejection rate depends mainly on the surface charge of the material which is correlated to the zeta potential.