Domain Bacteria Woese et al. 1990
   Phylum Proteobacteria Garrity and Holt 2001 see Phylum Proteobacteria Garrity et al. 2005
     Class "Alphaproteobacteria" Garrity and Holt 2001 nom. nud. see Class Alphaproteobacteria Garrity et al. 2006
       Order "Rhizobiales" see Order Rhizobiales Kuykendall 2006
         Family Rhizobiaceae Conn 1938 (Approved Lists 1980)
           Genus Agrobacterium Conn 1942 (Approved Lists 1980) see Genus Rhizobium Frank 1889 (Approved Lists 1980)
           Genus Allorhizobium de Lajudie et al. 1998 see Genus Rhizobium Frank 1889 (Approved Lists 1980)
           Genus Carbophilus Meyer et al. 1994
           Genus Chelatobacter Auling et al. 1993 see Genus Aminobacter Urakami et al. 1992
           Genus Ensifer Casida 1982
           Genus Sinorhizobium Chen et al. 1988
           1 Genus Rhizobium Frank 1889 (Approved Lists 1980)