A Gram-stain-negative, rod-shaped and facultatively anaerobic strain, designated CG51(T), was isolated from marine sediment collected from a coastal area in Weihai, PR China. Strain CG51(T) grew at 4-37 degrees C (optimum, 28-30 degrees C), with 1.0-6.0% (w/v) NaCl (2.0-3.0%) and at pH 6.0-8.5 (pH 7.0-7.5). The predominant fatty acids were iso-C-15:0, anteiso-C-15:0 and iso-C-14:0. Major polar lipids included an unidentified lipid and a phospholipid. The respiratory quinone was MK-7 and the genomic DNA G+C content was 35.9 mol%. The results of phylogenetic analysis based on 16S rRNA gene sequences placed strain CG51T in the genus Labilibacter with the close relatives being Labilibacter marinus Y11(T) and Labilibacter aurantiacus HQYD1(T), exhibiting 96.5 and 96.3% 16S rRNA pairwise similarity, values which are clearly below the 98.7% threshold value recommended for species demarcation. Based on the phylogenetic, physiological, chemotaxonomic and genetic data, strain CG51(T) represents a novel species within the genus Labilibacter, for which the name Labilibacter sediminis sp. nov. is proposed. The type strain is CG51(T) (=MCCC 1K03739(T)=JCM 33138(T)).