This brief gives a concise overview of nanoparticles and their microbial toxicity. It introduces various nanoparticles that are considered lethal to microbial cells (bacteria, virus and fungus) placing an emphasis on metal and metal oxide nanoparticles. The synthesis procedures (physical, chemical, microbial) that are often employed in their fabrication are also outlined. The interaction of various nanoparticles with microbes is described with attention given to the role of additives in the form of solvents, surfactants, capping materials. Commonly used experimental and analytical techniques...