Among all different types of nanoparticles used in nanomedicine, gold nanoparticles (GNPs) are the most investigated, because of their exceptional biocompatibility, unique optical properties and tremendous potential for various treatments that require a personalized approach. In this book, we analyzed various classical and green synthesis methods of GNPs that allow the control of shape, size and physical properties of these nanoparticles. Since non-toxic GNPs are a prerequisite for many biomedical applications, an integrated approach of biodistribution and cytotoxicity of GNPs as well as their functionalization, bioconjugation and stabilization methods were discussed within this book. Today, GNPs have a significant role in clinical diagnosis systems being used in many molecular and multimodal Imaging applications as well as in bio-sensing. Finally, the most recent scope widely expressed in medicine: the development and implementation of effective and personalized treatment, mainly for severe and debilitating disorders such as cancer is discussed and most recent advances revealed.