A Gram-stain-positive, spore-forming, rod-shaped and aerobic bacterium was isolated from a sediment sample from the South Sea in China. The isolate, designated H2(T), grew at 4-45 �XC (optimum 37 �XC) and pH 6-10 (optimum pH 7.0). The cell-wall peptidoglycan contained meso-diaminopimelic acid. The major isoprenoid quinone was MK-7 and the polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and an unknown aminophospholipid. The major fatty acid was iso-C(15 : 0). The genomic DNA G+C content of strain H2(T) was 44.8mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that the isolate formed a monophyletic clade with Bacillus firmus IAM 12464(T). DNA-DNA relatedness between the isolate and B. firmus ATCC 14575(T) was low (27.5 %). Strain H2(T) also had a phenotypic profile that readily distinguished it from its closest phylogenetic neighbours. It is evident from the combination of genotypic and phenotypic data that the organism should be classified in a novel species of the genus Bacillus, for which the name Bacillus oceanisediminis sp. nov. is proposed. The type strain is H2(T) (=CGMCC 1.10115(T) =JCM 16506(T)).