Plasma processes, initially developed for micro-electronics in the fifties, represent a clean and very flexible technology which has been used in many fields of the materials chemistry since the eighties. The potentialities of plasma processes in modifying or depositing thin layers on materials surface are exceptionally broad, hence their increasing interest for membrane applications. Depending on the nature of the gas used to create the plasma phase, plasma processes are likely to provide grafting, etching, cross-linking and/or deposition of a thin film on the surface of various materials with a high degree of flexibility leading to the manufacture of innovating membranes. Reviewing the most striking research works dealing with plasma membranes and pointing out the specificities of these membranes in term of structural and transport properties in comparison with more conventional membranes are the main objectives of the following text