Nanomaterials have a number of distinct features such as smaller size, high surface area, more reactivity, easy dispersability, and rapid diffusion that make them ideally suitable for environmental remediation besides other applications. It has been discussed in this monograph that properties of materials can be tailored to explore the possibilities of their applications to address challenging environmental problems faced today. Studies on the preparation of metal nanoparticles using both physical and chemical methods have been presented. Understanding and controlling the process parameters of metal nanoparticles growth during synthesis are considered the keys towards successful fabrication of materials with tailored properties. The relationships between the process parameters of Inert gas condensation and Sol-gel methods and their effects on the structure as well as properties of nanoparticles have been experimentally examined. Antibacterial characterization of these metal nanoparticles and nanocomposites has been carried out to investigate their possible uses as novel materials for environmental remediation and medicinal applications.