A novel, moderately halophilic, endospore-forming bacterial strain, designated Hal 1T, was isolated from a permafrost core collected from the Canadian high Arctic. The temperature for growth of strain Hal 1T was 0-30 degrees C with no growth observed at either -5 or 37 degrees C (optimum growth at about 25 degrees C). Strain Hal 1T was able to grow at NaCl concentrations of 0-20% (w/v) and did not have an absolute NaCl requirement for growth; optimal growth was at 5% (w/v) NaCl. The level of 16S rRNA gene sequence similarity between strain Hal 1T and the type strains of Virgibacillus carmonensis and Virgibacillus necropolis was 98.2%; values with respect to the type strains of other recognized Virgibacillus species were below 96.0%. The DNA G+C content of strain Hal 1T was 38.2 mol%. Levels of DNA-DNA relatedness between strain Hal 1T and the type strains of V. carmonensis and V. necropolis were 14.0 and 21.0%, respectively. The major fatty acid of strain Hal 1T was anteiso-C15:0, consistent with species of the genus Virgibacillus. The cell-wall peptidoglycan of strain Hal 1T was type A1alpha and the major respiratory quinone was MK-7. On the basis of genotypic and physiological results, strain Hal 1T (=DSM 19574T=JCM 14839T) is proposed as the type strain of a novel species of the genus Virgibacillus, namely Virgibacillus arcticus sp. nov.