The taxonomic position of a bacterium isolated from a marine sediment sample collected from the Bay of Bengal, Kanyakumari coast, India, was analyzed by using a polyphasic taxonomic approach. The isolated strain, designated as M-8(T), had phenotypic characteristics that matched those of the genus Bacillus and it represents a novel species. The diagnostic cell wall amino acid is meso-DAP. The major menaquinone is MK-7, and the strain has a phospholipid pattern of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and unknown glycolipid. The almost-complete 16S rRNA gene sequence (1,450 bases) of the novel strain was compared with those of closely related species and confirmed that the strain belongs to the genus Bacillus. 16S rRNA gene sequence analysis revealed that strain M-8(T) differs from the closely related species Bacillus horikoshi 99.5 %, Bacillus halmapalus 98.3 %, and Bacillus cohni 97.4 %. However, the DNA-DNA hybridization showed that it had genomic relatedness value of 60.7 % with B. horikoshi, B. halmapalus (37.6 %), and B. cohnii (29.9 %). The DNA G+C content of strain M-8(T) is 40.6 mol%. Based on the polyphasic data, strain M-8(T) should be recognized as a novel species of the genus Bacillus, for which the name Bacillus aequororis sp. nov. is proposed. The type strain is M-8(T) (= MTCC 11626(T) = JCM 19304(T)).