Strains of Gram-stain-negative, anaerobic, rod-shaped bacteria were isolated from chinchilla (Chinchilla lanigera) faeces, and strain ST166(T) was investigated taxonomically. Phylogenetic analyses of 16S rRNA gene sequences revealed that strain ST166(T) belonged to the genus Parabacteroides. Strain ST166(T) formed a distinct line of descent, and the highest sequence similarity to ST166(T) was found with Parabacteroides merdae JCM 9497(T) (95.6%) and Parabacteroides johnsonii JCM 13406(T) (95.0%). Analysis of hsp60 gene sequences also supported these relationships. Based on the phenotypic and phylogenetic characteristics, the novel species Parabacteroides chinchillae sp. nov. is proposed. The type strain of P. chinchillae sp. nov. is ST166(T) ( = JCM 17104(T) =CCUG 62154(T)).