The taxonomic status of a bacterium, strain DC-8(T), isolated from activated sludge, was determined using a polyphasic taxonomic approach. The cells of strain DC-8(T) were Gram-negative, non-motile, non-spore-forming and rod-shaped. The isolate grew at temperature range of 10-40 °C (optimum 30-35 °C), pH range of 5.0-10.0 (optimum 6.5-8.0) and NaCl concentrations of 0-5% (optimum 0-1%). The predominant menaquinone of strain DC-8(T) was MK-7 and major fatty acids were summed feature 3 (C16:1ω6c and/or C16:1ω7c; 39.7%), iso-C15:0 (33.7%) and C16:0 (5.2%). The DNA G+C content was 39.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequence comparison revealed that strain DC-8(T) was a member of the genus Sphingobacterium. Strain DC-8(T) shared the highest similarity with Sphingobacterium siyangense SY1(T) (98.4%), Sphingobacterium multivorum IAM 14316(T) (98.3%), Sphingobacterium canadense CR11(T) (98.0%) and Sphingobacterium detergens 6.2S(T) (97.9%) and shared less than 97% similarity with other members of the genus Sphingobacterium. DNA-DNA hybridization experiments showed that the DNA-DNA relatedness values between strain DC-8(T) and its closest phylogenetic neighbours were below 70%. Based on the phylogenetic analysis, DNA-DNA hybridization, whole-cell fatty acid composition as well as biochemical characteristics, strain DC-8(T) was clearly distinguished from all recognized species of the genus Sphingobacterium and should be classified as a representative of a novel species of the genus Sphingobacterium, for which the name Sphingobacterium caeni sp. nov. is proposed. The type strain is DC-8(T) (=CCTCC AB 2012020(T)=KACC 16850(T)).