A facultatively anaerobic, alkaliphilic, spore-forming, Gram-positive-staining rod, designated Y1T, was isolated under strictly anaerobic conditions from sediment of a soda lake in Jilin province, China. The strain was not dependent on Na+ but was highly halotolerant and grew optimally in medium JY with 0.5 M Na+ (0.06 M NaHCO3 and 0.44 M NaCl). The optimum pH for growth was 9.0, with a range of pH 7.5–10.5. No growth occurred at pH 7.0 or 11.0. The strain was mesophilic, with a temperature range of 15–45 °C and optimum growth at 32 °C. Strain Y1T was able to use certain mono- and oligosaccharides. Soluble starch and casein were hydrolysed. The methyl red test, Voges–Proskauer test and tests for catalase and oxidase activities were negative. The predominant fatty acids were anteiso-C15 : 0 and iso-C15 : 0. Comparative 16S rRNA gene sequence analysis revealed 93.4–96.8 % sequence similarity to members of the genus Amphibacillus. The DNA G+C content was 37.7 mol% (T m method). The DNA–DNA relatedness of strain Y1T with respect to Amphibacillus tropicus DSM 13870T and Amphibacillus sediminis DSM 21624T was 48 and 37 %, respectively. On the basis of its phylogenetic position and the DNA–DNA relatedness data as well as its physiological and biochemical properties, strain Y1T represents a novel species of the genus Amphibacillus, for which the name Amphibacillus jilinensis sp. nov. is proposed. The type strain is Y1T (=CGMCC 1.5123T =JCM 16149T).