A bacterial strain, designated IMCC26223T, was isolated from an oligotrophic freshwater lake, Lake Soyang, Korea. Cells of strain IMCC26223T were Gram-staining negative, strictly aerobic, non-motile and short-rod-shaped. Growth occurred at pH 6-8 (optimum, pH 7.0), at 4-25 °C (optimum, 15 °C) and with 0-0.5 % (w/v) NaCl (optimum, 0 %). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain IMCC26223T was identified as a member of the genus Flavobacterium and most closely related to Flavobacterium fluvii H7T (97.6 %), Flavobacterium segetis AT1048T (97.5 %) and Flavobacterium weaverense AT1042T (97.2 %). DNA-DNA relatedness between strain IMCC26223T and F. fluvii H7T was 41.5-51.7 % in the reciprocal hybridization. Strain IMCC26223T contained MK-6 as the major respiratory quinone. The major cellular fatty acids consisted of C16 : 0, iso-C15 : 0, anteiso-C15 : 0 and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), and the polar lipids were phosphatidylethanolamine, an unidentified aminolipid and two unidentified lipids. The DNA G+C content of strain IMCC26223T was 34.5 mol%. On the basis of 16S rRNA gene phylogeny and phenotypic characterization, strain IMCC26223T represents a novel species of the genus Flavobacterium, for which the name Flavobacterium soyangense sp. nov., is proposed. The type strain is IMCC26223T (=KCTC 52245T=JCM 31384T).