- Melkersson (-Rosenthal) syndrome 351.8
- Mellitus, diabetes - see Diabetes
- Melorheostosis (bone) (leri) 733.99
- Meloschisis 744.83
- Melotia 744.29
- Membrana
- Membranacea placenta - see Placenta, abnormal
- Membranaceous uterus 621.8
- Membrane, membranous - see also condition
- Membranitis, fetal 658.4
- Memory disturbance, loss or lack (see also Amnesia) 780.93
- Menadione (vitamin K) deficiency 269.0
- Menarche, precocious 259.1
- Mendacity, pathologic 301.7
- Mende's syndrome (ptosis-epicanthus) 270.2
- Mendelson's syndrome (resulting from a procedure) 997.3
- Ménétrier's disease or syndrome (hypertrophic gastritis) 535.2
- Ménière's disease, syndrome, or vertigo 386.00
- Meninges, meningeal - see condition
- Meningioma (M9530/0) - see also Neoplasm, meninges, benign
- Meningiomatosis (diffuse) (M9530/1) 237.6
- Meningism (see also Meningismus) 781.6