During studies of the microbiota of human faeces, five strains of Gram-negative anaerobic rods were isolated following growth in a polyamine-deficient medium. These strains belonged to the genus Bacteroides on the basis of 16S rRNA gene sequence data. 16S rRNA gene sequence similarity between one of the strains, 341T, and recognized species within the genus Bacteroides was <95 %. The DNA G+C content (44 mol%) and major fatty acid composition (anteiso-C(15 : 0), 32.0 %) supported the affiliation of strain 341(T) to the genus Bacteroides. Biochemical tests and DNA-DNA hybridization analysis demonstrated that strain 341T was distinct from Bacteroides uniformis and Bacteroides helcogenes, to which it was related most closely. On the basis of these data, a novel Bacteroides species, Bacteroides intestinalis sp. nov., is proposed with strain 341T (= JCM 13265T = DSM 17393T) as the type strain.