Four strains of a hitherto unknown bacterium isolated from vacuum-packaged refrigerated beef were characterized by using phenotypic and phylogenetic methods. The novel strains were Gram-positive, catalase-negative, psychrophilic, rod-shaped bacteria with lactic acid-homofermentative mechanism. Comparative 16S rDNA gene sequencing demonstrated that the unknown strains represent a novel subline within the genus Lactobacillus, close to but distinct from Lactobacillus curvatus and Lactobacillus sakei. The unknown strains were readily distinguished from all currently described members of the genus Lactobacillus by biochemical properties and SDS-PAGE whole-cell protein profiles. Based on phylogenetic and phenotypic evidence, it is proposed that the unknown bacterium be classified as Lactobacillus fuchuensis sp. nov. The type strain is strain B5M10T (= JCM 11249T = DSM 14340T).