In this paper was showed the most important decay fungi on willows, Salix sp., in middle part of the Danube basin which causes decay on wood. During research, fruit bodies of the fungi were collected on the field. Those fungi were identified in laboratory and then putted in herbarium. On the willows was found 28 species of fungus, which caused decay of wood. The most important fungus are: Fomes fomentarius (L.: Fr.) Fr. (syn. Ungulina fomentari (Linn.) Pat.), Phellinus igniarius (L. ex Fr.) Quel. and Trametes suavealens (L.: Fr.) Fr.