A novel strictly anaerobic, vancomycin-resistant, Gram-positive coccus (strain CCRI-16,110(T)) was isolated from a human faecal specimen. This strain was characterized using morphological, biochemical and molecular taxonomic methods. The organism was unable to hydrolyse aesculin and failed to produce acid from cellobiose, d-lactose and alpha-raffinose. Acetic acid was the sole product of glucose fermentation by the organism. On the basis of 16S rRNA and tuf gene sequence comparison, strain CCRI-16,110(T) was most closely related to species of the genus Ruminococcus and formed a hitherto unknown sublineage within the Clostridium coccoides rRNA cluster of organisms (cluster XIVa). Based on phenotypic and phylogenetic evidence, a novel species, Ruminococcus gauvreauii sp. nov., is proposed. The type strain is CCRI-16,110(T) (=NML 060141(T) =CCUG 54,292(T) =JCM 14987(T)).