- MacLeod, Colin Munro (1909-1972)
- Magnetotactic Bacteria
- Major Histocompatibility Complex (MHC)
- Malaria and the Physiology of Parasitic Infections
- Margulis, Lynn (1938- )
- Marine Microbiology
- Marshall, Barry J. (1951- )
- Mastigophora
- Matin, A. C. (1941- )
- Mccarty, Maclyn (1911- )
- Measles
- Medawar, Peter Brian (1915-1987)
- Medical Training and Careers in Microbiology
- Membrane Fluidity
- Meningitis, Bacterial and Viral
- Meselson, Matthew Stanley (1930- )
- Mesophilic Bacteria
- Metabolism
- Metchnikoff, Élie (1845-1916)
- Methane Oxidizing and Producing Bacteria
- Microbial Flora of the Oral Cavity, Dental Caries
- Microbial Flora of the Skin
- Microbial Flora of the Stomach and Gastrointestinal Tract
- Microbial Genetics
- Microbial Symbiosis
- Microbial Taxonomy
- Microbiology, Clinical
- Microorganisms
- Microscope and Microscopy
- Miller, Stanley L. (1930- )
