The experimental hydraulic resistance of a composite inorganic membrane can be much larger than the resistance obtained by summing all the layers resistances. This is explained by a transition boundary layer between two porous media of drastically different sizes. A new route of membrane synthesis is then proposed to minimize this effect. Noninfiltrated titania membranes of 0.2, 0.5 and 0.8 mu m mean pore diameter are compared to classical infiltrated membranes made with the same material under the same mechanical conditions. The noninfiltrated membranes have increased permeabilities of 30 to 70%. They are less sensitive to fouling by a suspension of ferric hydroxide particles and the limiting fluxes are considerably increased.