- Multilobed placenta - see Placenta, abnormal
- Multinodular prostate 600.10
- Multiparity V61.5
- Multipartita placenta - see Placenta, abnormal
- Multiple, multiplex - see also condition
- Mumps 072.9
- Mumu (see also Infestation, filarial) 125.9
- Münchausen syndrome 301.51
- Münchmeyer's disease or syndrome (exostosis luxurians) 728.11
- Mural - see condition
- Murmur (cardiac) (heart) (nonorganic) (organic) 785.2
- Murri's disease (intermittent hemoglobinuria) 283.2
- 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
- Myà's disease (congenital dilation, colon) 751.3
- Myalgia (intercostal) 729.1
- Myasthenia 358.00
