A taxonomic study was carried out on strain HYC-10(T), which was isolated from the intestinal tract contents of a flathead mullet, Mugil cephalus, captured from the sea off Xiamen Island, China. The bacterium was observed to be Gram positive, oxidase and catalase positive, rod shaped, and motile by subpolar flagella. The bacterium was found to grow at salinities of 0-12 % and at temperatures of 8-45 �XC. The isolate was found to hydrolyze aesculin and gelatin, but was unable to reduce nitrate to nitrite. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain HYC-10(T) belongs to the genus Bacillus, with highest sequence similarity (99.3 %) to Bacillus aerophilus 28K(T), Bacillus stratosphericus 41KF2a(T) and Bacillus altitudinis DSM 21631(T), followed by Bacillus safensis DSM 19292(T) (99.5 %) and Bacillus pumilus DSM 27(T) (99.5 %), while the sequence similarities to others were all below 97.6 %. The genomic ANIm values between strain HYC-10(T) and three type strains (B. altitudinis DSM 21631(T), B. safensis DSM 19292(T) and B. pumilus DSM 27(T)) were determined to range from 89.11 to 91.53 %. The DNA-DNA hybridization estimate values between strain HYC-10(T) and the three type strains were from 36.60 to 44.00 %. The principal fatty acids identified were iso-C15:0 (39.1 %), anteiso-C15:0 (22.7 %), iso-C17:0 (13.1 %), C16:0 (6.1 %), anteiso-C17:0 (5.8 %) and iso-C16:0 (5.1 %). The G+C content of the chromosomal DNA was determined from the draft genome sequence to be 41.3 mol%. The respiratory quinone was determined to be MK-7 (100 %). Phosphatidylglycerol, diphosphatidylglycerol, aminoglycolipid, two glycolipids and two unknown phospholipids were found to be present. The combined genotypic and phenotypic data show that strain HYC-10(T) represents a novel species of the genus Bacillus, for which the name Bacillus xiamenensis sp. nov. is proposed, with the type strain HYC-10(T) (=CGMCC NO.1.12326(T) = LMG 27143(T) = MCCC 1A00008(T)).