Nanoparticles have gained immense attention in cancer theranostic application due to their unusual physicochemical properties at the nanoscale. Green nanotechnology has generated an alternative option for eco-friendly synthesis of nanoparticles that show less toxicity and high efficacy. Biosynthesized gold and silver nanoparticles demonstrated various biomedical applications including cancer therapy and diagnosis. In the present chapter, recent advancements of biosynthesized gold and silver nanoparticles are discussed. Moreover we have discussed the emerging patents in the area of bionano-theranostics in cancer.