The spectacular progress of research in the nanotechnology field led to the achievement of important knowledge of materials at the atomic and molecular scale and the extent of the use of nanoparticles in the design of medical products, ecological processes, cosmetics and other biotechnological applications. One of the current focuses of the medical applications of nanotechnology is the development of new strategies to inhibit the activity of different microorganisms. The purpose of this review was to present the antimicrobial activity of metal cations in micro- and nanoparticulate forms and the dependence of this biological activity on shape, size and physico-chemical conditions.