Strawberry (Fragaria × ananassa Duch.) is an important cash crop in China. According to the 2016 China Agricultural Yearbook, Jiangsu Province is an important player in China’s strawberry market, with a cultivation area of 18,100 ha and production of 460,000 metric tons per year. We investigated a commercial field in the Jiangsu Province where the strawberry cultivar HongYan had been cultivated for more than 5 years. Between September and December 2017, symptoms of root and crown rot appeared in strawberry plants: plants developed disease symptoms characterized by yellowing of lower leaves, wilt, blight, and often death. The roots had a dark brown rot, and crowns were also rotted. The average incidence of the disease was up to 25%, and it even led to destruction and closure of a certain strawberry greenhouse. Root tissues (5 mm²) from 25 infected plants were excised from the central rotted root, surfaced sterilized by soaking in 75% ethyl alcohol for 30 s, rinsed three times in sterilized distilled water, and plated onto potato dextrose agar (PDA). All 25 isolates from each infected plant had the same morphological characteristics. They were able to grow at temperatures between 15 and 40°C, and there were no distinctive colony growth patterns on PDA. The sporangia were obovate or subglobose, papillate, and 21 to 34 × 20 to 28 µm in diameter. Oogonia were smooth and 22 to 30 µm in diameter. To confirm the identity of the pathogen, the rDNA internal transcribed spacer region (ITS, NCBI accession no. MT179561), cytochrome c oxidase I gene (cox I, MT188654), and cytochrome c oxidase II gene (cox II, MT188655) of three isolates were amplified and sequenced using the primer pairs ITS1/ITS4 (White et al. 1990), FM35/FM59, and FM66/FM58 (Martin 2000), respectively. BLAST analysis showed in all cases 98 to 100% identity with segments of Phytopythium helicoides (GenBank accession nos. MG597190.1 for ITS, KT258906.1 for cox I, and KT258907.1 for cox II). Based on the morphological features and the phylogenetic analyses of DNA sequences, the isolates were identified as P. helicoides. Pathogenicity assays were conducted on 3-week-old HongYan strawberry seedlings in September 2018. The roots of each seedling were dipped for 10 min into zoospore suspension of each isolate (1 × 10⁶ zoospores/ml), and the control seedlings were inoculated using the same procedure with sterilized distilled water. Five replicate seedlings were inoculated and planted individually into 1.8-liter free-draining pots containing sterilized soil. All the seedlings were incubated at 22°C under a 16-h light/dark regime and watered with 50 ml every 5 days. All inoculated plants showed root necrosis and crown rot 20 days after inoculation. The symptoms of inoculated seedlings were similar to the naturally infected plants. The same pathogen was reisolated from symptomatic roots and crowns. No symptoms were observed in the control seedlings. Although P. helicoides has been reported causing root and crown rot on strawberry in Japan and America (Ishiguro et al. 2014; Marin et al. 2019), rhizome rot on Asian lotus, and stem rot on Shatangju mandarin in China (Chen et al. 2016; Yin et al. 2016), it has not been reported in China from strawberry. Thus, strawberry growers should consider this pathogen when diagnosing and managing plant diseases in this crop.