- Impulsiveness 799.23
- Inaction, kidney (see also Disease, renal) 593.9
- Inactive - see condition
- Inadequate, inadequacy
- Inanition 263.9
- Inappropriate
- Inattention after or at birth 995.52
- Inborn errors of metabolism - see Disorder, metabolism
- Incarceration, incarcerated
- Incident, cerebrovascular (see also Disease, cerebrovascular, acute) 436
- Incineration (entire body) (from fire, conflagration, electricity, or lightning) - see Burn, multiple, specified sites
- Incised wound
- Incision, incisional
- Inclusion
- Incompatibility
- Incompetency, incompetence, incompetent
- Incomplete - see also condition
- Inconclusive
- Incontinence 788.30
- Incontinentia pigmenti 757.33
- Incoordinate
- Incoordination
