Two strains of Gram-reaction-negative, rod-shaped, non-spore-forming, non-motile, aerobic bacteria, designated LW30(T) and LW29, were isolated from the rhizosphere of a wetland reed in Dongtan, Chongming Island, China. The strains formed pale-yellow colonies on R2A plates. Growth occurred at 4-37 °C (optimum 30 °C), at pH 6-9 (optimum pH 7-8) and in the presence of 0-3 % (w/v) NaCl (optimum 0-1 %). Oxidase and catalase activities and flexirubin-type pigments were absent. MK-6 was the major respiratory quinone. The major fatty acids were iso-C(15 : 0), C(15 : 0), iso-C(15 : 1) G and iso-C(17 : 1)ω9c. Strains LW30(T) and LW29 could be differentiated from related species by several phenotypic characteristics. Phylogenetic analyses based on 16S rRNA gene sequences placed strains LW30(T) and LW29 in the genus Flavobacterium with high sequence similarity to Flavobacterium cheniae NJ-26(T) (94.0 %) and Flavobacterium indicium GPTSA 100-9(T) (93.9 %). Together with F. indicium GPTSA 100-9(T), strains LW30(T) and LW29 formed a distinct group in the phylogenetic tree. The DNA G+C content was 30 mol%. On the basis of the phylogenetic and phenotypic evidence, strains LW30(T) and LW29 represent a novel species of the genus Flavobacterium, for which the name Flavobacterium dongtanense sp. nov. is proposed. The type strain is LW30(T) (=KCTC 22671(T) =CCTCC AB 209201(T)).