An aerobic, Gram-reaction-positive, non-motile, psychrophilic bacterium, designated strain S6-3(T), was isolated from alpine soil. Cells exhibited a rod-coccus growth cycle and produced a yellow pigment. Growth occurred at 1-25 degrees C. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain S6-3(T) was related to members of the genus Arthrobacter, sharing highest sequence similarities with the type strains of Arthrobacter psychrolactophilus (97.9 %) and Arthrobacter stackebrandtii (97.6 %). Strain S6-3(T) had MK-9(H(2)) as the major menaquinone and anteiso-C(15 : 0) as the major fatty acid. The cell-wall peptidoglycan was of type A3alpha l-Lys-l-Thr-Ala(3). The predominant cell-wall sugars were galactose and rhamnose. The genomic DNA G+C content of strain S6-3(T) was 61.9 mol%. On the basis of phenotypic characteristics, phylogenetic analysis and DNA-DNA relatedness data, strain S6-3(T) is considered to represent a novel species of the genus Arthrobacter, for which the name Arthrobacter alpinus sp. nov. is proposed. The type strain is S6-3(T) (=DSM 22274(T) =CGMCC 1.8950(T)).