Two Gram-stain-positive strains, YIT 12363(T) and YIT 12364(T), were isolated from human faeces. They were rod-shaped, non-motile, asporogenous, facultatively anaerobic and did not exhibit catalase activity. Comparative analyses of 16S rRNA, pheS and rpoA gene sequences demonstrated that the novel strains were members of the genus Lactobacillus. On the basis of 16S rRNA gene sequence similarity, the type strains of Lactobacillus casei (95.3% similarity), Lactobacillus paracasei subsp. paracasei (95.6%), Lactobacillus paracasei subsp. tolerans (95.3%) and Lactobacillus rhamnosus (95.4%) were the closest neighbours to strain YIT 12363(T). For strain YIT 12364(T), the highest similarity values were observed with the type strains of Lactobacillus diolivorans, Lactobacillus parafarraginis and Lactobacillus rapi (95.8, 96.0 and 96.0%, respectively). Phenotypic and genotypic features demonstrated that these strains each represent a separate novel species of the genus Lactobacillus, and the names Lactobacillus saniviri sp. nov. (type strain YIT 12363(T)=JCM 17471(T)=DSM 24301(T)) and Lactobacillus senioris sp. nov. (type strain YIT 12364(T)=JCM 17472(T)=DSM 24302(T)), respectively, are proposed.