WOS: 000363091600042Forests ecosystems are sources of oxygen and wood products, also they prevent soil erosion, improve water and air quality, serve as homes for wildlife; and therefore, they preserve and increase biodiversity. Forests can host a diverse community of fungal species with various effects on their host trees. In this research, trees of Fagaceae family of Uludag forests of Bursa province were investigated between the years of 2002 and 2008. By microscopic examination we identified 38 microfungi species in 27 genera belongs to Ascomycota and 1 microfungus species in 1 genus belongs to Basidiomycota. The taxa belong to 15 families: Botryosphaeriaceae, Diaporthaceae, Diatrypaceae, Dothioraceae, Erysiphaceae, Gnomoniaceae, Incertae sedis, Melanconidaceae, Microstromataceae, Nectriaceae, Pseudovalsaceae, Rhytismataceae, Trichosphaeriaceae, Valsaceae and Xylariaceae. The distribution of species by trophic groups revealed a dominance of xylotrophic species. With this study, fungal diversity of Fagaceae family in Uludag forests was identified and included in the mycobiota of Turkey