A novel strain of a Gram-stain negative, non-motile, non-spore forming rod-shaped, obligate anaerobic bacterium, designated AT11(T), was isolated from a stool sample of a morbidly obese woman living in Marseille, France. This bacterium was characterized using biochemical, chemotaxonomic, and phylogenetic methods. The 16S rRNA gene sequence analysis showed that strain AT11(T) had a 97.8% nucleotide sequence similarity with Eisenbergiella tayi strain B086562(T), the closest species with standing in nomenclature. The major cellular fatty acids of the novel isolate were C-16(:0) followed by saturated or unsaturated C-18 fatty acids (C(18:1)n9, C(18:1)n5 and C-18:0). The draft genome of strain AT11(T) is 7,114,554 bp long with 48% G+C content. 6176 genes were predicted, including 6114 protein-coding genes and 62 were RNAs (with 25S rRNA genes, two 16S rRNA genes, two 23S rRNA genes, and 56 tRNA genes). The digital DNA-DNA hybridization (dDDH) related-ness between the new isolate and E. tayi strain B086562(T) was 23.1% +/- 2.2. Based on the phenotypic, chemotaxonomic, genomic, and phylogenetic characteristics, Eisenbergiella massiliensis sp. nov., is proposed. The type strain is AT11(T) (= DSM 100838(T) = CSUR P2478(T)).