Development of nanoparticles (NPs) as a part of cancer therapeutics has given rise to a new field of research – cancer nanomedicine. In comparison to traditional anti-cancer drugs, NPs provide a targeted approach which prevents undesirable effects. In this communication, we have reviewed the role of gold and silver NPs (AgNPs) in the cancer nanomedicine. The preparation of gold NPs (AuNPs) and AgNPs can be grouped into three categories – physical, chemical and biological. Among the three approaches, the biological approach is growing and receiving more attention due to its safe and effective production. In this review, we have discussed important methods for synthesis of gold and AgNPs followed by techniques employed in characterization of their physicochemical properties, such as UV–visible spectroscopy, electron microscopy (TEM and SEM) and size and surface analysis (DLS). The mechanism of formation of these NPs in an aqueous medium through various stages – reduction, nucleation and growth has also been reviewed briefly. Finally, we conclude our review with the application of these NPs as anti-cancer agents and numerous mechanisms by which they render cancer cell toxicity.