Self-supported porous zeolite membranes have been prepared in a simple but effective way using cellulose acetate membranes as templates. The spongy zeolite membranes possess unique ramified pore structures in three levels (see Figure), i.e., interconnected micrometer-sized macropores among the zeolitic microtubes, channel-like submicrometer-sized pores inside the microtubes, and zeolite micropores (< 1 nm) on microtube walls.