A haloalkaliphilic Gram-positive bacterium, strain 6AG^T, that grew aerobically at an optimum temperature of 37 °C and at pH 7–10 (optimum 9·0), was isolated from algal mat from a mineral pool located in Malvizza in the Campania region (southern Italy). The isolate tolerated high concentrations of NaCl, up to 25 %. On the basis of 16S rRNA gene sequence similarity, the strain was shown to belong to the genus Bacillus. Analysis of the 16S rRNA gene sequence revealed high similarity between strain 6AG^T and an unidentified isolate from Hailaer soda lake (China) (99·9 % identity) and two Kenyan isolates, 3E1 and WE4 (98·3 and 97·8 % identity, respectively). The G+C content of the DNA was 48·4 mol%. The predominant respiratory quinones were MK-7(H₂), MK-7(H₄) and DMK-7(H₂); phosphatidylglycerol and diphosphatidylglycerol were the predominant polar lipids. iC15 : 0 and aiC15 : 0 were the major fatty acids. Strain 6AG^T accumulated osmolytes. The phylogenetic distance of strain 6AG^T (=DSM 15402^T=ATCC BAA-957^T) from any recognized species within the genus Bacillus allowed it to be classified as the type strain of Bacillus saliphilus sp. nov.