The genomic relatedness among 16 strains assigned to the moderately halophilic species Deleya halophila and other 20 representative strains of halophilic and nonhalophilic species was estimated by determination of deoxyribonucleic acid (DNA) base composition and by DNA-DNA hybridization studies. The guanine-plus-cytosine (G + C) base contents, determined from the melting temperature of DNAs of D. halophila strains, were 66.0-68.8 mol %. DNA-DNA homology studies, determined by membrane filter technique, indicate that the 16 strains of D. halophila comprise a genetically homogeneous group. High homology (greater-than-or-equal-to 70-100%) was obtained between the type strain D. halophila CCM 3662 and the other D. halophila strains studied; however, very low DNA relatedness was found between the representative strains of D. halophila and other Deleya species (greater-than-or-equal-to 13-0%), as well as other moderately halophilic, marine, or nonhalophilic bacteria investigated.