- Acidopenia 288.59
- Acidosis 276.2
- Aciduria 791.9
- Acladiosis 111.8
- Aclasis
- Acleistocardia 745.5
- Aclusion 524.4
- Acmesthesia 782.0
- Acne (pustular) (vulgaris) 706.1
- Acneiform drug eruptions 692.3
- Acnitis (primary) (see also Tuberculosis) 017.0
- Acomia 704.00
- Acontractile bladder 344.61
- Aconuresis (see also Incontinence) 788.30
- Acosta's disease 993.2
- Acousma 780.1
- Acoustic - see condition
- Acousticophobia 300.29
- Acquired - see condition
- Acquired immune deficiency syndrome - see Human immunodeficiency virus (disease) (illness) (infection)
- Acquired immunodeficiency syndrome - see Human immunodeficiency virus (disease) (illness) (infection)
- Acragnosis 781.99