A Gram-negative, pleomorphic, aerobic, haloalkaliphilic archaeon, strain 167-74(T), was isolated from commercial rock salt imported into Japan from China. Phylogenetic analysis based on 16S rRNA gene sequence similarities showed that strain 167-74(T) is closely related to Halostagnicola larsenii XH-48(T) (98.3 %) and Halostagnicola kamekurae 194-10(T) (97.2 %). The major polar lipids of the isolate were C(20)C(20) and C(20)C(25) derivatives of phosphatidylglycerol and phosphatidylglycerol phosphate methyl ester. A glycolipid was not detected, in contrast to the two existing, neutrophilic species of the genus Halostagnicola. The DNA G+C content of strain 167-74(T) was 60.7 mol%. and it gave DNA-DNA reassociation values of 19.5 and 18.8 %, respectively, with Hst. larsenii JCM 13463(T) and Hst. kamekurae 194-10(T). Therefore, strain 167-74(T) represents a novel species, for which the name Halostagnicola alkaliphila sp. nov. is proposed, with the type strain 167-74(T) ( = JCM 16592(T) = CECT 7631(T)).