- Martin's disease 715.27
- Martin-Albright syndrome (pseudohypoparathyroidism) 275.49
- Martorell-Fabre syndrome (pulseless disease) 446.7
- Masculinization, female, with adrenal hyperplasia 255.2
- Masculinovoblastoma (M8670/0) 220
- Masochism 302.83
- Masons' lung 502
- Mass
- Massive - see condition
- Mast cell
- Mastalgia 611.71
- Masters-Allen syndrome 620.6
- Mastitis (acute) (adolescent) (diffuse) (interstitial) (lobular) (nonpuerperal) (nonsuppurative) (parenchymatous) (phlegmonous) (simple) (subacute) (suppurative) 611.0
- Mastocytoma (M9740/1) 238.5
- Mastocytosis 757.33
- Mastodynia 611.71
- Mastoid - see condition
- Mastoidalgia (see also Otalgia) 388.70
- Mastoiditis (coalescent) (hemorrhagic) (pneumococcal) (streptococcal) (suppurative) 383.9
- Mastopathy, mastopathia 611.9
- Mastoplasia 611.1
- Masturbation 307.9