Supports for microfiltration and ultrafiltration were prepared with Tunisian silty marls. Plastic pastes were prepared from a ceramic powder of silty marls mixed with organic additives and water. The pastes could be extruded to elaborate a porous tubular configuration. The supports fired at 1190degreesC and characterised by mercury porosimetry showed pore diameters centred near 9.2 mum and porosity about 50%. Microfiltration membranes were also prepared from Tunisian silty marls. The preparation of this ceramic layer was performed by the slip casting method. A deflocculated slip was obtained by mixing a mineral powder, PVA (12 wt %), and water. The water permeability measured for the membranes calcinated at 1000degreesC and with a mean pore size of 0.4 mum is 867 l.h(-1).m(-2).bar(-1). These membranes can be used in tangential microfiltration.