Porous metal wafers and thin films were produced by selectively etching the rod phase of the directionally solidified eutectics NiAl&sngbnd;Cr and NiAl&sngbnd;Mo and by a two‐state replication process, respectively. The 0.5‐&mgr;‐diam holes were uniform in size and distribution with densities as high as 8.5×107holes/cm2. The flow properties of these porous membranes were tested using three liquids of different viscosity and were found to be in agreement with Poisseuille's law.