A Gram-positive, yellow-pigmented bacterium, strain KOPRI 21702(T), was isolated from sea sand on King George Island, Antarctica. Cells were irregular rods with peritrichous flagella; their optimum growth temperature was 23-26 degrees C. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the Antarctic isolate formed a distinct phyletic line in a clade of the genus Sanguibacter and showed highest sequence similarity (97.7%) to the type strain of Sanguibacter keddieii. The major isoprenoid quinone, predominant cellular fatty acids and DNA G+C content were consistent with placement of the Antarctic isolate in the genus Sanguibacter. Phylogenetic analysis and differences in physiological and biochemical characteristics between strain KOPRI 21702(T) and the four recognized Sanguibacter species indicate that the isolate represents a novel species of this genus. The name Sanguibacter antarcticus sp. nov. (type strain KOPRI 21702(T) =KCTC 13143(T) =JCM 14623(T) =DSM 18966(T)) is proposed for this isolate.