Coptis chinensis Franchet, is a perennial herb used as a traditional Chinese medicine. Annual production of Coptis is about 3000 tons in Shizhu, Chongqing. In recent years, root rot has become a serious and widespread disease on Coptis in Shizhu with an average incidence of 40%, and yield losses up to 67%. Infected plants were easy to pull from the soil, and most of the fibrous roots and main roots were brown or black compared to healthy roots that were yellow. Severely infected plants were wilted and necrotic. In October 2019, 33 diseased roots were collected from Shizhu (30°18'N, 108°30'E), and small samples (0.5 cm in length) were cut from the border between diseased and healthy tissue, successively sterilized with 75% ethanol and 2% sodium hypochlorite, rinsed 3 times with sterilized water, dried on sterilized filter paper, and transferred onto PDA, and incubated at 25°C for 7 days in dark. Eighteen distinct fungal isolates (H1-H18) were isolated and Koch's postulates were conducted to verify the pathogenicity of individual isolates. The rhizosphere soil of healthy 2-year-old Coptis plants was inoculated by pouring 5 mL of conidial suspension (106 conidia/mL) scraped from a culture of each isolate on PDA. Sterilized water was used to mock inoculate. For each isolate, 6 plants were inoculated. After 20 days, the roots of all plants inoculated with H15 or H18 were dark brown and rotten, while mock inoculated plants were healthy. The isolates H15 and H18 were re-isolated from symptomatic plants. Isolate H15 formed abundant white mycelium on PDA and produced rose pigment in the agar. Conidia were long and slender, straight to slightly curved, with 1-3 septate. The apical cells were tapering and bent, and the foot cells were distinctly notched. Conidiogenous cells were monophialides and polyphialides. No chlamydospores were observed (Figure S1). Isolate H18 formed white sparse mycelium on PDA and produced no pigment in the agar. Conidia were relatively wide, straight and stout, with 3-5 septate. The apical cells were blunt and rounded, and the foot cells were barely notched. Conidiogenous cells were long monophialides. Chlamydospores were formed intercalary in the hyphae (Figure S2). For further identification, the internal transcribed spacer (ITS), β-tubulin, translation elongation factor 1ɑ (EF1ɑ) and RNA polymerase second largest subunit (RPB2) gene regions were amplified with ITS1/ITS4, Bt2a/Bt2b, EF1/EF2 and 5f2/7cr (White et al. 1990; Glass and Donaldson, 1995; O'Donnell et al. 2010). GenBank accession numbers of H15 and H18 were MT463390 and MT463389 for the ITS region, MT465656 and MT465654 for β-tubulin, MT653321 and MT465651 for EF1ɑ, and MT653323 and MT653322 for RPB2. BLAST results showed the ITS, β-tubulin, EF1ɑ, and RPB2 sequences revealed 100% (533/533 base pairs), 100% (265/265 base pairs), 98% (622/632 base pairs), and 99% (936/947 base pairs) homology respectively with those of Fusarium avenaceum (MN186746.1, MH791368.1, KU238140.1, and MK185027.1), and 100% (537/537 base pairs), 100% (227/227 base pairs), 100% (688/688 base pairs), and 99.03% (918/927 base pairs) with F. solani in GenBank (MH857319.1, MN692929.1, KP674211.1, and MH300549.1), respectively. Thus, H15 and H18 were identified as F. avenaceum and F. solani based on its morphological and molecular characteristics. To our knowledge, F. solani has been previously reported as a pathogen on Coptis (Luo et al. 2014), and this is the first report of root rot on Coptis caused by F. avenaceum in the world. Identification of the pathogens is important for effective disease management and control.