One of the basic tasks in the field of biodeterioration is to recognise the microbial species responsible for the destruction of particular substrates, and to identify factors impacting the level of damage caused by microorganisms. Even in 1839, it was known that there existed some fungi capable of attacking keratinized tissues, although, at that time, only dermatophytes were recognised. The relevant literature pertaining to microbiological deterioration of keratinous substrates includes 299 fungi belonging to 100 genera. Representatives of the genera Aspergillus, Penicillium, Chrysosporium, Fusarium, Microsporum, Trichophyton, and Acremonium appear to be the most common. Of the 299 species collected, 107 belonging primarily to the Onygenales and Eurotiales are pathogenic to humans. The research focusing on microbial ability to colonize and destroy keratinous materials has been carried out mainly on sheep fleece, hairs, and feathers, but only a few authors have dealt with woollen fabric biodeterioration, which is of particular significance for the preservation of antique textiles. (C) 2009 Elsevier Ltd. All rights reserved.