A novel Gram-stain-negative, non-spore-forming, orange-pigmented bacterium, designated strain SS2-56T, was isolated from sediment of the Nakdong River in Sangju-si, Republic of Korea. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the isolate SS2-56T belongs to the family Chitinophagaceae, and was most closely related to Lacibacter daechungensis H32-4T (96.6 % similarity) and Lacibacter cauensis NJ-8T (96.1 %). Strain SS2-56T contained menaquinone 7 (MK-7) as a respiratory quinone and iso-C15 : 0, iso-C17 : 0 3-OH, iso-C15 : 1 G, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0 as major fatty acids. The major polar lipids of strain SS2-56T were phosphatidylethanolamine, one unidentified aminophospholipid and four unidentified lipids. The DNA G+C content was 43.8 mol%. Phenotypic, chemotaxonomic and phylogenetic evidence clearly indicates that strain SS2-56T represents a novel species of the genus Lacibacter, for which the name Lacibacter nakdongensis sp. nov. is proposed. The type strain is SS2-56T (=KCTC 52160T=JCM 31372T).