Fifteen strains of extremely halophilic bacteria were isolated from fish sauce (nam-pla) collected in Thailand at various stages of the fish-fermentation process. The isolates were strictly aerobic, spore-forming, Gram-positive rods. They grew optimally in the presence of 20-26 % NaCl. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The predominant menaquinone was MK-7. The major cellular fatty acids were anteiso-C(15 : 0) and anteiso-C(17 : 0). Polar lipid analysis revealed the presence of phosphatidylglycerol, diphosphatidylglycerol and two unidentified glycolipids. The DNA G+C content was 42.1-43.1 mol%. On the basis of the 16S rRNA gene sequence, a representative strain, PS11-2(T), was found to be closely related to Lentibacillus juripiscarius JCM 12147(T) (97.3 % similarity). The 15 strains were included in the same species on the basis that the levels of DNA-DNA relatedness with strain PS11-2(T) were greater than 70 %. They could be distinguished from L. juripiscarius and other Lentibacillus species on the basis of several phenotypic characteristics and low levels of DNA-DNA relatedness (</=19.4 %). Therefore, the strains represent a novel species of the genus Lentibacillus, for which the name Lentibacillus halophilus sp. nov. is proposed. The type strain is PS11-2(T) (=JCM 12149(T)=TISTR 1549(T)=PCU 240(T)).