Inorganic microfiltration membranes with a pore size down to 0.1 mu m have been made using laser interference lithography and silicon micro machining technology. The membranes have an extremely small flow resistance due to a thickness smaller than the pore size, a high porosity and a very narrow pore size distribution. They are relatively insensible to fouling, because they have a smooth surface, short pore channels and because they can be operated in cross flow configuration at very low transmembrane pressures. Experiments with yeast cell filtration of beer show a minimal fouling tendency and a flux that is about 40 times higher than in conventional diatomaceous earth filtration. The uniform pore distribution makes the membranes suitable for many other applications like critical cell to cell separation, particle analysis systems, absolute filtrations and model experiments.