A Gram-reaction-positive, facultatively anaerobic, non-spore-forming and catalase-negative rod-shaped bacterial strain, designated IWT126(T), was isolated from orchardgrass (Dactylis glomerata L.) silage preserved in Hachimantai, Iwate, Japan. The isolate showed growth at 15-45 �XC, pH 3.5-7.5 and with 4.0 % (w/v) NaCl. The cell wall peptidoglycan did not contain meso-diaminopimelic acid, and the DNA G+C content was 45.6 mol%. The major cellular fatty acids were C16 : 0 and C19 : 1 cyclo 9,10. Based on 16S rRNA gene sequence similarity, strain IWT126(T) was classified as a member of the genus Lactobacillus and was most closely related to Lactobacillus odoratitofui YIT 11304(T) (98.7 %), Lactobacillus similis JCM 2765(T) (98.5 %), Lactobacillus collinoides JCM 1123(T) (97.6 %), Lactobacillus paracollinoides DSM 15502(T) (97.6 %) and Lactobacillus kimchicus DCY51(T) (96.9 %). Based on sequence analysis of the phenylalanyl-tRNA synthase �\-subunit (pheS) gene, strain IWT126(T) was well separated from its phylogenetic neighbours in the genus Lactobacillus. Based on physiological, biochemical and genotypic results, as well as low DNA-DNA relatedness to recognized phylogenetic relatives in the genus Lactobacillus, classification of strain IWT126(T) as a representive of a novel species named Lactobacillus silagei sp. nov. is proposed. The type strain is IWT126(T) (= JCM 19001(T) = DSM 27022(T)).