Chifin and chitosan are biopolymers from renewable resources, obtainable from shells of shellfish, the wastes of the seafood industry. Their distinctive advantages include availability, biocompatibility, biodegradability, nontoxicity, antimicrobial properties, heavy metal ions chelation, gel forming properties, ease of chemical modification, and high affinity to proteins. Owing to these characteristics, the polymers, thus far underutilized, are predicted to be widely exploited in the near future in environmentally benign applications, notably in systems working in biological environments. This paper looks at how chitin/chitosan materials can contribute to the development of membrane-based processes, particularly to those classified as supportive of the sustainability of our life, i.e. controlled release, biosensors, tissue engineering, and the ones contributing to cleaner industries, a cleaner environment, and cleaner water and food. (C) 2004 Elsevier B.V. All rights reserved.