- Anergasia (see also Psychosis, organic) 294.9
- Anesthesia, anesthetic 782.0
- Anetoderma (maculosum) 701.3
- Aneuploidy NEC 758.5
- Aneurin deficiency 265.1
- Aneurysm (anastomotic) (artery) (cirsoid) (diffuse) (false) (fusiform) (multiple) (ruptured) (saccular) (varicose) 442.9
- Angiectasis 459.89
- Angiectopia 459.9
- Angiitis 447.6
- Angina (attack) (cardiac) (chest) (effort) (heart) (pectoris) (syndrome) (vasomotor) 413.9
- Angioblastoma (M9161/1) - see Neoplasm, connective tissue, uncertain behavior
- Angiocholecystitis (see also Cholecystitis, acute) 575.0
- Angiocholitis (see also Cholecystitis, acute) 576.1
- Angiodysgensis spinalis 336.1
- Angiodysplasia (intestinalis) (intestine) 569.84
- Angioedema (allergic) (any site) (with urticaria) 995.1
- Angioendothelioma (M9130/1) - see also Neoplasm, by site, uncertain behavior
- Angiofibroma (M9160/0) - see also Neoplasm, by site, benign
- Angiohemophilia (A) (B) 286.4
- Angioid streaks (choroid) (retina) 363.43
- Angiokeratoma (M9141/0) - see also Neoplasm, skin, benign
- Angiokeratosis