Three Gram-negative, non-motile, non-spore-forming short rods (strains PB56(T), PB180, PB229) were isolated from soil in South Korea. Cells were orange-red in colour. Strains PB180 and PB229 contained small amounts of bacteriochlorophyll a, which was not detected in strain PB56(T). However, all three isolates contained the genes for the photosynthetic type II reaction centre, pufLM. They contained Q-10 as the dominant quinone and C(18 : 1) as the dominant fatty acid. The highest 16S rRNA gene sequence similarities were found to Sphingomonas oligophenolica JCM 12082(T) (95.8 %), Sphingomonas koreensis KCTC 2882(T) (95.1 %), Sphingomonas mali IFO 15500(T) (95.1 %), Sphingomonas faeni DSM 14747(T) (94.8 %), Sphingomonas pruni IFO 15498(T) (94.7 %) and Sphingomonas aquatilis KCTC 2881(T) (94.6 %), as well as to Sphingosinicella microcystinivorans Y2(T) and Sphingosinicella xenopeptidilytica 3-2W4(T) (95.0-95.2 %). Phylogenetic analyses supported the assignment of strains PB56(T), PB180, PB229 to the genus Sphingomonas. The novel isolates differ from all established species of the genus Sphingomonas by their higher G+C content and the absence of straight-chain 2-hydroxy fatty acids. Based on the phylogenetic distances from species with validly published names and their phenotypic properties, the strains constitute a separate species, for which the name Sphingomonas kaistensis sp. nov. is proposed. The type strain is PB56(T) (=KCTC 12334(T)=DSM 16846(T)).