Strains of the recently proposed species Bacteroides chinchillae share more than 99.4 % 16S rRNA gene sequence similarity with the type strain of Bacteroides sartorii although these two species do not appear to be similar from their published descriptions. The aim of this study was to perform phenotypic and genetic analyses of both species to clarify their taxonomic position. B. chinchillae JCM 16497(T) exhibited high hsp60 gene sequence similarity with B. sartorii JCM 17136(T) (100 %) as well as B. chinchillae JCM 16498 (100 %). The hsp60 gene sequence analysis and levels of DNA-DNA relatedness observed demonstrated B. sartorii JCM 17136(T), B. chinchillae JCM 16497(T), and B. chinchillae JCM 16498 are members of a single species. Based on these data, we propose Bacteroides chinchillae as a later heterotypic synonym of Bacteroides sartorii. An emended description of B. sartorii is provided.