- Metatarsus, metatarsal - see also condition
- Methemoglobinemia 289.7
- Methemoglobinuria (see also Hemoglobinuria) 791.2
- Methicillin-resistant staphylococcus aureus (MRSA) V09.0
- Methioninemia 270.4
- Metritis (catarrhal) (septic) (suppurative) (see also Endometritis) 615.9
- Metropathia hemorrhagica 626.8
- Metroperitonitis (see also Peritonitis, pelvic, female) 614.5
- Metrorrhagia 626.6
- Metrorrhexis - see Rupture, uterus
- Metrosalpingitis (see also Salpingo-oophoritis) 614.2
- Metrostaxis 626.6
- Metrovaginitis (see also Endometritis) 615.9
- Mexican fever - see Typhus, Mexican
- Meyenburg-Altherr-Uehlinger syndrome 733.99
- Meyer-Schwickerath and Weyers syndrome (dysplasia oculodentodigitalis) 759.89
- Meynert's amentia (nonalcoholic) 294.0
- Mibelli's disease 757.39
- Mice, joint (see also Loose, body, joint) 718.1
- Micheli-Rietti syndrome (thalassemia minor) 282.49
- Michotte's syndrome 721.5
- Micrencephalon, micrencephaly 742.1