- HOOD (hereditary osteo-onychodysplasia) 756.89
- Hooded
- Hookworm (anemia) (disease) (infestation) - see Ancylostomiasis
- Hoppe-Goldflam syndrome 358.00
- Hordeolum (external) (eyelid) 373.11
- Horn
- Horner's
- Horseshoe kidney (congenital) 753.3
- Horton's
- Hospice care V66.7
- Hospitalism (in children) NEC 309.83
- Hourglass contraction, contracture
- Household circumstance affecting care V60.9
- Housemaid's knee 727.2
- Housing circumstance affecting care V60.9
- HTLV-I infection 079.51
- HTLV-II infection 079.52
- HTLV-III (disease) (illness) (infection) - see Human immunodeficiency virus (disease) (illness) (infection)
- HTLV-III/LAV (disease) (illness) (infection) - see Human immunodeficiency virus (disease) (illness) (infection)
- Huchard's disease (continued arterial hypertension) 401.9
- Hudson-Stähli lines 371.11
- Huguier's disease (uterine fibroma) 218.9