A Gram-stain-negative, strictly aerobic, non-motile, non-spore-forming, yellow, rod-shaped bacterium, designated S-II-13(T), was isolated from ground water at Daejeon in Korea. Strain S-II-13(T) grew between 15 and 30 °C (optimal growth at 28 °C), between pH 6.0 and 9.0 (optimal growth at pH 7.5) and at salinities of 0.3-1.5 % (w/v) NaCl, growing optimally with 0.5 % (w/v) NaCl. On the basis of 16S rRNA gene sequence analysis, strain S-II-13(T) was found to belong to the genus Sphingobium, showing closest phylogenetic similarity to Rhizorhapis suberifaciens CA1(T) (97.0 % 16S rRNA gene sequence similarity), Sphingobium sufflavum HL-25(T) (96.9 %) and Sphingobium vulgare HU1-GD12(T) (96.6 %). The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylcholine and sphingoglycolipid. The predominant ubiquinone was Q-10. The major fatty acids were C18 : 1&#9697c, C14 : 0 2-OH, C16 : 0 and summed feature 3 (C16 : 1&#9697c and/or iso-C15 : 0 2-OH). The DNA G+C content of strain S-II-13(T) was 63.5 mol%. DNA-DNA relatedness between strain S-II-13(T) and Rhizorhapis suberifaciens LMG 17323(T), Sphingobium sufflavum KCTC 23953(T) and Sphingobium vulgare KCTC 22289(T) was 24, 52 and 55 %, respectively. On the basis of evidence from this taxonomic study using a polyphasic approach, strain S-II-13(T) represents a novel species of the genus Sphingobium for which the name Sphingobium subterraneum sp. nov. is proposed. The type strain is S-II-13(T) (&#8202= KACC 17606(T)&#8202= NBRC 109814(T)).