A pink-red pigmented, non-motile, coccoid bacterial strain, ST0316^T, was isolated from dust samples collected from the stratosphere in Japan. Phylogenetic analysis based on 16S rRNA gene sequences showed that it belonged to the genus <italic>Deinococcus</italic>. DNA G+C content (69.8 mol%), desiccation tolerance, and resistance to gamma-rays [D₁₀ (dose required to reduce the bacterial population by 10-fold) &gt;8 kGy] and UV radiation (D₁₀ 1000 J m⁻²) supported the affiliation of strain ST0316^T to the genus <italic>Deinococcus</italic>. The major peptidoglycan amino acids were <sc>d</sc>-glutamic acid, glycine, <sc>d</sc>-alanine, <sc>l</sc>-alanine and ornithine. Predominant fatty acids were C_16 : 1
<italic>ω</italic>7<italic>c</italic>, C_16 : 0, C_17 : 0 and iso-C_17 : 0. Strain ST0316^T diverged from recognized species of the genus <italic>Deinococcus</italic>, showing less than 93.0 % similarity values to its closest relatives <italic>Deinococcus apachensis</italic>, <italic>D. aerius</italic>, <italic>D. geothermalis</italic> and <italic>D. murrayi</italic>. Strain ST0316^T also differed from the type strains of closely related species in its polar lipid profile, nitrate reduction and carbon-source assimilation tests. Therefore, we propose a new species of the genus <italic>Deinococcus</italic>, <italic>Deinococcus aetherius</italic> sp. nov. (type strain, ST0316^T =JCM 11751^T =DSM 21230^T).