Metals and their derivative compounds have been used as therapeutic agents from historical times until the present day. Recently, there has been tremendous development in the formulation of nanomaterials toward human benefit, among which silver and gold nanoparticles (AuNPs) have gained major attention due to their ease of preparation, low toxicity, and their quick attachment to the biological surfaces. As numerous works have been carried out with silver nanoparticles, AuNPs are discussed in this chapter. Due to their photo-optical distinctiveness and biocompatibility, AuNPs have proven to be a very impressive device in various nanomedical applications. The capability of manipulating their size and geometry allows their optical and physical properties to be controlled. Their ability to conjugate easily with different systems enhances their anticancer properties. So, they have been widely investigated to enable drug delivery, sustained drug release, molecular targeting, and additional therapeutic and imaging functions. In the following chapter, we explore the properties and potential of AuNPs and their role in diagnostics, surgery, and medicine. © 2016 Elsevier Inc. All rights reserved.