Microporous zirconia-titania composite membranes have been fabricated by sol-gel processing using diethanolamine-modified precursor solutions. Microporous materials made from powders calcined at 400 degrees C show type I nitrogen sorption behavior. Supported similar to 0.1 mu m thick membranes (see figure) exhibit molecular-sieving properties and are expected to have great potential for separation and reaction applications under harsh conditions.