A psychrotolerant sulfate-reducing bacterium, designated B15^T, was isolated from supercooled water brine from within permafrost of the Varandey Peninsula, on the southern coast of the Barents Sea. Cells were Gram-negative, motile vibrions (3.0–4.0×0.4–0.5 µm) with a single polar flagellum. The isolate was positive for desulfoviridin as a bisulfite reductase. Strain B15^Tgrew at −2 to 28 °C (optimum 24 °C) and with 0–2.0 % NaCl (optimum 0.2 %). The isolate used H₂plus acetate, formate, ethanol, lactate, pyruvate and choline as electron donors and used sulfate, sulfite, thiosulfate, elemental sulfur, DMSO and Fe³⁺as electron acceptors. Pyruvate and lactate were not fermented in the absence of sulfate. The G+C content of genomic DNA was 55.2 mol%. Analysis of the 16S rRNA gene sequence showed that the isolate belonged to the genusDesulfovibrio. Its closest relatives wereDesulfovibrio idahonensisCY1^T(98.8 % 16S rRNA gene sequence similarity) andDesulfovibrio mexicanusLup1^T(96.5 %). On the basis of genotypic, phenotypic and phylogenetic characteristics, the isolate represents a novel species, for which the nameDesulfovibrio arcticussp. nov. is proposed; the type strain is B15^T( = VKM B-2367^T = DSM 21064^T).