Using cooling and lubricating in process fluids contaminate the technological process. These contaminations have a negative effect on decreasing the fluids and changes in their functional attributes, which can be strongly expressed not only by inappropriate actions of the fluid during the technological process but also by increased economic costs. Using nanoparticles as biocide additive has a high efficiency due to their high chemical and biological activity. Over the past decade, there has been a strong push toward the development of silver-containing materials for commercial use that exhibit antimicrobial or bactericidal properties. Silver nanoparticles are considered one of the ways to inhibit bacteria and improve biological, chemical, and technological stability of the process fluids. This chapter is divided into four parts. The first part reports the different metals that are used to prepare the nanoparticles. The second part deals with the silver nanoparticles and their preparation using physical and chemicals routes. The third part demonstrates the antimicrobial and biological activity of silver nanoparticles and also their particle size is influenced by the synthesis conditions such as medium, pH, and stabilizing agents used. The solvent used in the reaction has a great influence on their nature and stability. The fourth part reports the feature of using silver nanoparticles in tribological applications, including lubricants, cutting fluid, and metalworking fluids, as nanoadditives. Silver nanoparticles have several applications in the tribological field.