A Gram-negative, motile, non-spore-forming and moderately halophilic rod-shaped strain, SW-45T, was isolated from sea water of the East Sea in Korea. The organism grew optimally at 30-37 degrees C and grew at 4 and 46 degrees C. It grew in the presence of 0.5-18% (v/w) NaCl, with an optimum of 2-7% NaCl. Strain SW-45T was chemotaxonomically characterized by having ubiquinone-9 (Q-9) as the major respiratory lipoquinone and C16 : 0, C18 : 1omega9c and C16 : 1omega9c as the predominant fatty acids. The DNA G + C content was found to be 55 mol%. Phylogenetic analysis based on 16S rDNA sequences showed that strain SW-45T forms a coherent cluster with the clade comprising the two Marinobacter species. 16S rDNA sequence similarities between strain SW-45T and the Marinobacter species was 94.9% to Marinobacter hydrocarbonoclasticus DSM 8798T and 95.3% to Marinobacter aquaeolei DSM 11845T. Levels of DNA-DNA relatedness between strain SW-45T and the type strains of M. hydrocarbonoclasticus and M. aquaeolei were respectively 4.3 and 5.5%. On the basis of phenotypic properties, phylogeny and genomic data, strain SW-45T (=KCCM 41591T =JCM 11547T) should be placed in the genus Marinobacter as a member of a novel species, for which the name Marinobacter litoralis sp. nov. is proposed. As part of this study, the major respiratory lipoquinone of M. hydrocarbonoclasticus and M. aquaeolei was also found to be Q-9.