- Muscae volitantes 379.24
- Muscle, muscular - see condition
- Musculoneuralgia 729.1
- Mushroom workers' (pickers') lung 495.5
- Mushrooming hip 718.95
- Mutation
- Mutism (see also Aphasia) 784.3
- MVD (microvillus inclusion disease) 751.5
- Myà's disease (congenital dilation, colon) 751.3
- Myalgia (intercostal) 729.1
- Myasthenia 358.00
- Myasthenic 728.87
- Mycelium infection NEC 117.9
- Mycetismus 988.1
- Mycetoma (actinomycotic) 039.9
- Mycobacteriosis - see Mycobacterium
- Mycobacterium, mycobacterial (infection) 031.9
- Mycosis, mycotic 117.9
- Mydriasis (persistent) (pupil) 379.43
- Myelatelia 742.59
- Myelinoclasis, perivascular, acute (postinfectious) NEC 136.9 [323.61]
- Myelinosis, central pontine 341.8
