A novel actinomycete, designated strain KLBMP 1279(T), was isolated from surface-sterilized roots of a coastal halophyte, Salicornia europaea Linn., collected from Jiangsu Province, in the east of China. The taxonomic status of this organism was established using a polyphasic approach. 16S rRNA gene sequence analysis indicated that strain KLBMP 1279(T) was closely related to Modestobacter marinus 42H12-1(T) (99.5% 16S rRNA gene sequence similarity), Modestobacter versicolor CP153-2(T) (98.4%) and Modestobacter multiseptatus AA-826(T) (97.5%). Chemotaxonomic characteristics were consistent with its assignment to the genus Modestobacter in that the isolate had meso-diaminopimelic acid as the diagnostic diamino acid in the cell wall, MK-9(H4) as major menaquinone and a polar lipid profile containing diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannosides, two unknown aminophospholipids and an unknown phospholipid. The predominant fatty acids were iso-C16:0, iso-C15:0 and C17:1ω8c. The DNA G+C content was 71.7 mol%. However, DNA-DNA hybridization assays as well as physiological and biochemical analyses differentiated strain KLBMP 1279(T) from its closest phylogenetic relatives. On the basis of phenotypic, chemotaxonomic and phylogenetic evidence, the isolate KLBMP 1279(T) represents a novel species of the genus Modestobacter, for which the name Modestobacter roseus sp. nov. is proposed; the type strain is KLBMP 1279(T) (=KCTC 19887(T)=NBRC 108673(T)=DSM 45764(T)). An emended description of the genus Modestobacter is also proposed.