Haemophilus
influenzae - sp.

Hafnia
alvei

Haliscomenobacter
hydrossis

Halobacillus
halophilus - karajensis - litoralis - trueperi

Halomonas
anticariensis - aquamarina - cupida - desiderata - elongata - halmophila - halodurans - halophila - muralis - pacifica - pantelleriensis - sp. - subglaciescola - venusta

Helcococcus
kunzii

Helicobacter
acinonychis - bilis - cinaedi - fennelliae - hepaticus - muridarium - mustelae - pametensis - pullorum - pylori - sp.

Herbaspirillum
autotrophicum - huttiense - lusitanum - rubrisubalbicans - seropedicae

Herellea
caseolytica - lwoffii - sp.

Herminiimonas
fonticola

Hoeflea
marina

Hongiella
mannitolivorans - ornithinivorans

Hydrogenophaga
flava - palleronii - pseudoflava - taeniospiralis

Hylemonella
gracilis

Hymenobacter
aerophilus - sp.