Two Gram-stain-negative, aerobic, motile, halophilic, rod-shaped bacteria, designated Hb8 T and Hb20, were isolated from a tidal flat environment located on the South-West Korean peninsula. The isolates grew at 10-37 C, at pH 5.0-9.0 and in NaCl concentrations of 0.5-15 % (w/v; optimum, 3.0-6.0 %). Sequence analysis of the 16S rRNA indicated that the isolates belong to the genus Marinobacter and are most closely related to Marinobacter sediminum R65 T (98.3 %), followed by Marinobacter lipolyticus SM19 T , Marinobacter salsuginis SD-14B T and Marinobacter similis A3d10 T . The overall 16S rRNA gene sequence similarity with these species was 97.9 %, but Hb8 T and Hb20 showed 100 % sequence similarity with each other. DNA-DNA relatedness values of H8 T and Hb20 suggested that these isolates represent a single species, while DNA-DNA relatedness values of the two novel isolates with M. sediminum DSM 27079 T and M. similis DSM 15400 T were only 21.3 and 22.9 %, respectively. The major fatty acids present in strain Hb8 T were identified as C 16 : 0 , C 16 : 1 !9c, C 18 : 1 !9c, C 18 : 0 3-OH and summed feature 3 (C 16 : 1 !6c and/or C 16 : 1 !7c). Ubiquinone-9 was the main respiratory quinone in both the novel strains. The polar lipids found to be present included diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, four unidentified phospholipids and five unidentified lipids. The genomic DNA G+C content of Hb8 T and Hb20 was 54.5 mol%. Polyphasic analysis indicated that the two isolates are representatives of a novel species of the genus Marinobacte, for which the name Marinobacter salinus sp. nov. is proposed. The type strain is Hb8 T (=KCTC 52255 T =JCM 31416 T ).The genus Marinobacter belongs to the family Alteromonadaceae, of the order Alteromonadales, class Gammaproteobacteria, and was first described by Gauthier et al.[1] to accomodate a hydrocarbon-degrading bacterium. At the time of writng, the genus Marinobacter comprises 40 species with validly published names (www.bacterio.net) isolated from a diverse range of environments including seawater [2,3], marine sand [4], marine sediment [5], the brine-seawater interface [6], coastal hot springs, saline soil [7], wastewater from wine production [8] and even laboratory cultures from dinoflagellates [9]. Members of the genus Marinobacter are Gram-stain-negative, oxidase-and catalase-positive, halophilic and rod-shaped [1]. Several species of the genus Marinobacter (i.e. Marinobacter aquaeolei, Marinobacter maritimus and Marinobacter algicola) have been associated with aromatic and aliphatic hydrocarbon degradation [1,2,[9][10][11]. This may indicate a functional role in the organic carbon cycle, as they constitute one of the dominant bacterial community groups in contaminated environments [12]. The objectives of this study were to classify two newly isolated marine bacteria obtained when studying the diversity of halophilic bacteria associated with the marine environment.Strains Hb8 T and Hb20 were isolated from tidal flat sediment sample...