Two moderately halophilic, gram-positive, heterotrophic bacterial strains were isolated from hypersaline sediments of the Great Salt Lake in Utah, These two strains, designated SL-4(T) (T = type strain) and SL-ST, were motile, spore forming, strictly aerobic rods which contained peptidoglycan of the Orn-D-Asp type in their vegetative cell walls, The guanine-plus-cytosine contents of the DNAs of strains SL-4(T) and SL-5(T) were 42 and 43 mol%, respectively, A detailed investigation of the phenotypic and phylogenetic characteristics of these organisms revealed that each isolate represents a new species that is closely related to Sporosarcina halophila, a moderately halophilic, spore-forming coccus, Phylogenetic data indicate that there is only a distant relationship between Sporosarcina halophila and Sporosarcina ureae, the type species of the genus Sporosarcina. The sequences of the 16S rRNA genes of strain SL-4(T) and Salinicoccus roseus DSM 5351 were determined, We propose that a new genus, Halobacillus, should be created; this genus includes Halobacillus halophiles (formerly Sporosarcina halophila) as the type species, as well as Halobacillus litoralis DSM 10105(T) (= SL-4(T)) and Halobacillus trueperi DSM 10404(T) (= SL-5(T)).