Abstract: The forest pathogens of root and butt rot in Northeast China are reported,and 49 species are recorded.The host,type of rot and distribution of each species are given according to field inventory.Most of these species are white rot fungi,but some species cause brown rot.Antrodiella albocinnamomea,Armillaria ostoyae,Bjerkandera fumosa,Funalia trogii,Heterobasidion parviporum,Inonotus obliquus,Inonotus pruinosus,Leucophellinus irpicoides,Melanoporia castanea,Onnia tomentosa,Oxyporus sinensis,Parmastomyces taxi,Perenniporia macckiae,Perenniporia subacida,Phellinidium sulphurascens,Phellinus cf.laricis,Phellinus vaninii,Pholiota squarrosoides,Phylloporia ribis,Polyporus fraxineus,Sparassis brevipes,Spongipellis delectans are new pathogens to Chinese forests.The names of some Chinese wood-rotting fungi are re-studied,and they are now treated based on the modern taxonomic system.Some forest pathogens are re-named by interfertility tests, e.g., Armillaria ostoyae,Heterobasidion parviporum and Phellinus yamanoi etc.