Chitin was isolated from various natural sources including Cuban lobsters, Sanlucar prawns. Norway lobsters, Squills, Spanish crayfish, American crayfish and Fusarium oxysporum with a yield of 14-25% on a dry basis. The physico-chemical properties of chitin from the different sources were studied by IR spectroscopy and scanning electron microscopy, and its degree of acetylation was determined. The chitin thus obtained is suitable for biotechnological applications (e.g. as supporting material for immobilizing enzymes).