Chestnut (Castanea sativa Mill.) forests in Greece occupy 33 000 ha of mostly mountainous land and are considered to be wild, native ecosystems. They are managed mainly for timber production. One of the secondary products is edible mushrooms, which in recent years have been harvested on a heavy commercial scale in several parts of the country. Chestnut coppice ecosystems, as well as old-growth chestnut forests, make excellent habitats for a rich mycoflora. The main objective of the present study was to survey the fungal biodiversity in chestnut ecoystems because 1) the mycoflora comprises one of the main components in these ecosystems, 2) the results could be fed into conservation policy. Nearly 170 species of parasitic fungi of chestnut and macrofungi (Basidiomycotina and Ascomycotina), classified as mycorrhizal, saprotrophic and wood decay fungi, are discussed in this paper.