Rahnella
aquatilis - genomospecies

Ralstonia
pickettii

Raoultella
ornithinolytica - planticola - terrigena

Rarobacter
faecitabidus - incanus

Rathayibacter
iranicus - rathayi - toxicus - tritici

Renibacterium
salmoninarum

Rhizobium
etli - galegae - hainanense - huautlense - leguminosarum - lupini - mongolense - radiobacter - rhizogenes - rubi - undicola - vitis

Rhodobacter
azotoformans - blasticus - capsulatus - sphaeroides

Rhodobium
marinum

Rhodoblastus
acidophilus

Rhodococcus
coprophilus - equi - erythropolis - fascians - globerulus - koreensis - marinonascens - opacus - percolatus - rhodnii - rhodochrous - ruber - sp. - wratislaviensis - zopfii

Rhodopseudomonas
palustris - rhenobacensis

Rhodospirillum
rubrum

Riemerella
anatipestifer - columbina

Roseivivax
halodurans - halotolerans

Roseobacter
denitrificans - gallaeciensis - litoralis

Roseomonas
cervicalis - fauriae - genomospecies - gilardii

Roseovarius
tolerans

Rothia
dentocariosa - mucilaginosa - nasimurium

Rubrimonas
cliftonensis

Rubrobacter
radiotolerans - xylanophilus

Ruegeria
algicola - atlantica - gelatinovorans

Ruminococcus
hansenii