A novel moderately halophilic bacterium belonging to the genus Halomonas was isolated from brine samples collected from Ezzemoul sabkha in north-eastern Algeria. The cells of strain 5-3(T) were Gram-negative, rod-shaped and non-motile. The strain was catalase- and oxidase-positive and produced an exopolysaccharide. Growth occurred at NaCl concentrations of 5-25% (optimum at 7.5%), at 30-50 degrees C (optimum at 37-40 degrees C) and at pH 6.0-9.0 (optimum at pH 7.5). The major fatty acids were C(12:0) 3-OH, C(16:1)omega7c/iso-C(15:0) 2-OH, C(16:0), C(18:1)omega7c and C(19:0)omega8c cyclo. The G+C content of the genomic DNA was 57.0 mol% (T(m)). The affiliation of strain 5-3(T) with the genus Halomonas was confirmed by 16S rRNA gene sequence comparisons. The most closely related species was Halomonas halmophila, which showed a 16S rRNA gene sequence similarity of 99.7%. However, the level of DNA-DNA relatedness between the novel isolate and the related Halomonas species was less than 31.4%. On the basis of the data from this polyphasic study, strain 5-3(T) represents a novel species of the genus Halomonas, for which the name Halomonas sabkhae sp. nov. is proposed. The type strain is 5-3(T) (=CECT 7246(T)=DSM 19122(T)=LMG 24084(T)).