Rhizoma Paridis Paris polyphylla var. chinensis is an economically important medicinal plant in China. In May 2014, stem rot on Rhizoma Paridis caused by a Fusarium species was observed in Chongren (North Fujian, China). Plants in the early infection stages exhibited brown, water-soaked stem lesions near the ground, which elongated and enlarged. Later, leaves turned yellow and the plants wilted. Disease incidence was 10–30%. Fungal isolates with fluffy, white mycelia and pale purple pigments were obtained on potato saccharose agar (PSA). Microconidia were single-celled and oval to reniform, 4.8–9.4 × 1.8–3.5 μm in size. Macroconidia were 1–4-septate, falciform or fusiform, and slightly curved, ranging from 31.7 to 48.7 × 2.5 to 4.9 μm. Chlamydospores were both terminal and intercalary, either solitary or in short chains. Conidiogenous cells were short and monophialidic. These morphological characteristics accorded with the description of F. oxysporum (Burgess et al. 1994). The internal transcribed spacer (ITS) region sequences of the ribosomal DNA of 13 fungal isolates obtained using ITS5a and ITS4 primers produced a nucleotide sequence about 520 bp long (accession Nos. KU931542–53); when compared with sequences from database, all 13 fungal isolates and three F. oxysporum isolates (JF439473, EU839370, and EU839398) formed a distinct lineage with a bootstrap value of 88.0%. Moreover, the thirteen fungal isolates, using species-specific FOF1/FOR1 F. oxysporum primers, produced 340 bp target fragments. Five 18-month-old seedlings of Rhizoma Paridis were incubated with a conidial suspension (106/ml), at 28 °C and 80–90% humidity with a 12-h photoperiod. The controls were roots immersed in sterile deionized water. Fifteen to 18 days after inoculation, brown spots appeared on the stems of 60% of inoculated plants, and parts of the leaves turned from green to yellow. The fungus was successfully reisolated from the decayed stems of inoculated plants. To our knowledge, this is first report of F. oxysporum as a pathogen of P. polyphylla var. chinensis in Chongren, North Fujian, China, or worldwide.