Silver has long been known to show antibacterial activity but it was only the development of the nanotechnology which allowed to create substances and materials of the new generation. Preparations with embedded silver nanoparticles exhibit even stronger biocidal effects against a wide spectrum of harmful microorganisms, i.e. bacteria, fungi and viruses (even HIV). Multidirectional activity of nanosilver compromises the induction of microbial defensive mechanisms and stops the development of bacterial resistance. Nanostructured silver damages the cell structure, affects energy metabolism and the genetic material of microorganisms. The nanosilver parameters are dependent on its shape, size and an engineering mode. Nanoscale silver bound to solid surface has been incorporated in wound dressings as it was demonstrated to reduce wound bioburden, prevent or treat local infection. The studies are also conducted on silver nanoparticles application in implantology and tissue engineering as well as in food industry for disinfection of air and food production areas. The evidence-based scientific assessment of nanosilver highlights its relatively low toxicity to humans.