A Gram-negative, non-motile, rod-shaped bacterial strain, ODN7(T), was isolated from a wastewater treatment plant in Korea, and its taxonomic position was investigated by use of a polyphasic taxonomic approach. Strain ODN7(T) grew optimally at around pH 7.5 and 30 degrees C and in the presence of 0-0.5 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain ODN7(T) fell within the cluster comprising species of the genus Sphingomonas, clustering with Sphingomonas panni C52(T), with which it shared highest 16S rRNA gene sequence similarity (98.9 %). The chemotaxonomic properties of strain ODN7(T) were consistent with those of the genus Sphingomonas. The predominant ubiquinone was Q-10, and the major fatty acids were C(18 : 1)omega7c, C(16 : 1)omega7c and/or iso-C(15 : 0) 2-OH, and C(16 : 0). Major polar lipids were sphingoglycolipid, phosphatidylcholine, phosphatidylglycerol and phosphatidylethanolamine. The DNA G+C content of strain ODN7(T) was 67.2 mol%. Strain ODN7(T) exhibited levels of DNA-DNA relatedness of 15-32 % to the type strains of phylogenetically related Sphingomonas species and could be differentiated from these species based on differences in phenotypic characteristics. On the basis of the data presented, strain ODN7(T) is considered to represent a novel species of the genus Sphingomonas, for which the name Sphingomonas hankookensis sp. nov. is proposed. The type strain is ODN7(T) (=KCTC 22579(T)=CCUG 57509(T)).