Four gamma- and UV-radiation-resistant bacterial strains, designated TDMA-24(T), TDMA-24-2, TDMA-24-3 and TDMA-24-4, were isolated from a fresh-water sample collected at Misasa, Tottori, Japan. Cells of these strains were Gram-reaction-positive, non-motile, non-spore-forming, rod-shaped and formed red colonies. The genomic DNA G+C contents ranged from 70.5 to 70.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the novel isolates belong to the genus Deinococcus, the highest sequence similarities being with Deinococcus aquaticus PB314(T) (98%) and Deinococcus caeni Ho-08(T) (97 %). The polar lipid profile of strain TDMA-24(T) comprised three unidentified phosphoglycolipids, five unidentified glycolipids and seven unidentified polar lipids. MK-8 was the predominant respiratory quinone. Major fatty acids were iso-C(15 : 0), C(15 : 1)ω6c, C(15 : 0), C(16 : 0) and summed feature 3 (iso-C(15 : 0) 2-OH and/or C(16 : 1)ω7c). On the basis of their phylogenetic positions and chemotaxonomic and phenotypic characteristics, the novel isolates represent a novel species of the genus Deinococcus, for which the name Deinococcus depolymerans sp. nov. is proposed. The type strain is TDMA-24(T) ( = JCM 14369(T) = NBRC 102115(T) = CCUG 53609(T)).