- Hypomania, hypomanic reaction (see also Psychosis, affective) 296.0
- Hypomastia (congenital) 611.82
- Hypomenorrhea 626.1
- Hypometabolism 783.9
- Hypomotility
- Hyponasality 784.44
- Hyponatremia 276.1
- Hypoparathyroidism (idiopathic) (surgically induced) 252.1
- Hypoperfusion (in)
- Hypopharyngitis 462
- Hypophoria 378.40
- Hypophosphatasia 275.3
- Hypophosphatemia (acquired) (congenital) (familial) 275.3
- Hypophyseal, hypophysis - see also condition
- Hypophyseothalamic syndrome 253.8
- Hypopiesis - see Hypotension
- Hypopigmentation 709.00
- Hypopinealism 259.8
- Hypopituitarism (juvenile) (syndrome) 253.2
- Hypoplasia, hypoplasis 759.89
- Hypopotassemia 276.8
- Hypoproaccelerinemia (see also Defect, coagulation) 286.3