- Microvillus inclusion disease (MVD) 751.5
- Micturition
- Middle
- Midplane - see condition
- Miescher's disease 709.3
- Miescher-Leder syndrome or granulomatosis 709.3
- Mieten's syndrome 759.89
- Migraine (idiopathic) 346.9
- Migrant, social V60.0
- Migratory, migrating - see also condition
- Mikulicz's disease or syndrome (dryness of mouth, absent or decreased lacrimation) 527.1
- Milian atrophia blanche 701.3
- Miliaria (crystallina) (rubra) (tropicalis) 705.1
- Miliary - see condition
- Milium (see also Cyst, sebaceous) 706.2
- Milk
- Milk-leg (deep vessels) 671.4
- Milkers' nodes 051.1
- Milkman (-Looser) disease or syndrome (osteomalacia with pseudofractures) 268.2
- Milky urine (see also Chyluria) 791.1
- Millar's asthma (laryngismus stridulus) 478.75
- Millard-Gubler paralysis or syndrome 344.89