Dermatitis digitalis is an economically important ulcerative disease of undetermined aetiology affecting the hooves of cattle. Material was examined from two independent cases of this disease in Switzerland. Cultures from the advancing front of both lesions yielded large numbers of closely related short, mesophilic, non-motile, non-spore-forming, anaerobic, proteolytic, Gram-positive rods. The 16S rRNA gene sequences of strains OMZ 913(T) and OMZ 915 were identical and indicate Tindallia magadiensis and Eubacterium saphenum as their closest relatives. Phenotypically, the novel isolates are clearly distinguished from related bacteria by protein and antigen patterns, by cellular fatty acids and by API ZYM activities. The diamino acid of the Gram-positive cell wall is ornithine and the G+C content of OMZ 913(T) DNA is 44.4 mol%. The phylogenetic distance from recognized taxa in the phylum Firmicutes is sufficient to place these bovine isolates into a novel genus and species, for which the name Guggenheimella bovis gen. nov., sp. nov. is proposed, with OMZ 913(T) (=CIP 108087(T)=DSM 15657(T)) as the type strain.