Botrytis cinerea (teleomorph: Botryotinia fuckeliana) is an airborne, necrotrophic ascomycete plant pathogen, which has been reported to infect over 200 crop hosts worldwide (Boddy 2016; Kim et al. 2016). B. cinerea can cause severe damage to plants, such as gray mold on leaves or rot on fruit, both pre- and postharvest (Dean et al. 2012). In September 2015, brown, irregular-shaped lesions were observed on peanut leaves from Jilin province in China. Disease incidence in approximately a 10-ha area in each of 15 examined fields was 20 to 30%. Symptoms were initially observed on the apex and/or margin of the older leaves, were not restricted by the leaf veins, and enlarged to result in leaf necrosis and defoliation. Symptomatic leaf samples were collected, surface sterilized (75% ethanol, 30 s; 3% NaClO, 2 min), rinsed in sterile water three times, and air dried; small sections were plated on potato dextrose agar (PDA) medium and incubated at 25 ± 1°C (12-h photoperiod). Colonies on PDA medium were initially gray and covered the entire plate with aerial mycelium in 2 days. Black sclerotia were first observed at the edge of colonies after 3 days and then formed unevenly among the colonies after 6 days. Conidia were transparent, elliptical or ovoid, and measured 4.4 to 8.6 µm long × 3.4 to 5.8 µm wide (n = 50). For pathogenicity tests, a conidial suspension (10⁵ conidia/ml) was sprayed onto leaves of peanut plants grown in five 16 × 12-cm pots with six plants per pot. A similar number of plants were inoculated with sterile water to serve as controls. Inoculated plants were incubated in a growth cabinet with a high relative humidity (80%) for 72 h at 25°C, followed by 60 to 70% relative humidity at 25°C with a 12-h photoperiod of dark and light. Symptoms on leaves emerged between 7 and 10 days and were similar to those described on the field-collected leaves, whereas no symptoms were observed on the control plants. The pathogen that was reisolated from the inoculated leaves using the same method described above had the same morphology on PDA medium as described above. As for molecular identification, the internal transcribed spacer (ITS) and three nuclear protein-coding genes (glyceraldehydes-3-phosphate dehydrogenase gene [G3PDH], heat-shock protein 60 gene [HSP60], and DNA-dependent RNA polymerase subunit gene [RPB2]) were amplified using primer pairs ITS1/ITS4 (White et al. 1990), G3PDH-F/G3PDH-R, HSP60-F/HSP60-R, and RPB2-F/RPB2-R (Staats et al. 2005), respectively. The sequences were submitted to GenBank (ITS, MN272329; G3PDH, MK791186; HSP60, MK791187; RPB2, MK791188). BLASTn analysis showed 500/501, 994/994, 1,120/1,120, and 1,240/1,240 base pairs matched with sequences of B. cinerea deposited for ITS (MH763647), G3PDH, (MH479930), HSP60 (MH796663), and RPB2 (MH713610), respectively. To our knowledge, this is the first report of B. cinerea found on peanut plant in China. B. cinerea usually causes soft rotting of aerial plant parts and postharvest rotting of vegetables, fruits, and flowers (Williamson et al. 2007). The threat of this pathogen to peanut pods needs to be further investigated, because it could potentially lower the peanut quality and may be a threat to human health.