- Ablutomania 300.3
- Abnormal, abnormality, abnormalities - see also Anomaly
- Abnormally formed uterus - see Anomaly, uterus
- Abnormity (any organ or part) - see Anomaly
- ABO
- Abocclusion 524.20
- Abolition, language 784.69
- Aborter, habitual or recurrent NEC
- Abortion (complete) (incomplete) (inevitable) (with retained products of conception) 637.9
- Abortus fever 023.9
- Aboulomania 301.6
- Abrachia 755.20
- Abrachiatism 755.20
- Abrachiocephalia 759.89
- Abrachiocephalus 759.89
- Abrami's disease (acquired hemolytic jaundice) 283.9
- Abramov-Fiedler myocarditis (acute isolated myocarditis) 422.91
- Abrasion - see also Injury, superficial, by site
- Abrikossov's tumor (M9580/0) - see also Neoplasm, connective tissue, benign
- Abrism 988.8
- Abruptio placentae - see Placenta, abruptio
- Abruption, placenta - see Placenta, abruptio