- Human immunodeficiency virus (disease) (illness) 042
- Human immunodeficiency virus-2 infection 079.53
- Human papillomavirus 079.4
- Human parvovirus 079.83
- Human T-cell lymphotrophic virus I infection 079.51
- Human T-cell lymphotrophic virus II infection 079.52
- Human T-cell lymphotropic virus-III (disease) (illness) (infection) - see Human immunodeficiency virus (disease) (illness) (infection)
- Humpback (acquired) 737.9
- Hunchback (acquired) 737.9
- Hunger 994.2
- Hunner's ulcer (see also Cystitis) 595.1
- Hunt's
- Hunter (-Hurler) syndrome (mucopolysaccharidosis II) 277.5
- Hunter's glossitis 529.4
- Hunterian chancre 091.0
- Huntington's
- Huppert's disease (multiple myeloma) (M9730/3) 203.0
- Hurler (-Hunter) disease or syndrome (mucopolysaccharidosis II) 277.5
- Hürthle cell
- Hutchinson's
- Hutchinson-Boeck disease or syndrome (sarcoidosis) 135
- Hutchinson-Gilford disease or syndrome (progeria) 259.8
