- Anthracosis (lung) (occupational) 500
- Anthrax 022.9
- Anthropoid pelvis 755.69
- Anthropophobia 300.29
- Antibioma, breast 611.0
- Antibodies
- Antibody deficiency syndrome
- Anticoagulant, circulating (see also Circulating anticoagulants) 286.5
- Antimongolism syndrome 758.39
- Antimonial cholera 985.4
- Antisocial personality 301.7
- Antithrombinemia (see also Circulating anticoagulants) 286.5
- Antithromboplastinemia (see also Circulating anticoagulants) 286.5
- Antithromboplastinogenemia (see also Circulating anticoagulants) 286.5
- Antitoxin complication or reaction - see Complications, vaccination
- Anton (-Babinski) syndrome (hemiasomatognosia) 307.9
- Antritis (chronic) 473.0
- Antrum, antral - see condition
- Anuria 788.5
- Anus, anal - see condition
- Anusitis 569.49
- Anxiety (neurosis) (reaction) (state) 300.00