Currently, bioconjugates and nanocarriers can be practically used in drug discovery, therapy, diagnosis, imaging, targeting, stability, etc. Also preparing nano drug carrier systems (NDCSs) is a common application of bio-conjugates. Current examples of bio-conjugates are nanoparticles, liposomes, micelles, dendrimers, quantum dots, carbon nanotubes, nano-fibers, but not limited to. As bioconjugates, nano drug carrier systems have important roles in the development of intelligent drugs such as tailor made drugs and drug targeting systems for early diagnosis steps and therapy. Currently, different drug carrier systems can be designed for improvement of the physico-chemical properties of drugs, controlling drug release, stability, in vivo performance and modification of the surface chemistry of drugs by using nanotechnology, bioconjugation and PEGylation. The anticancer efficacy of existing chemotherapeutic drugs can be improved by employing formulation, bioconjugation and nano-technological approaches. This current review focuses on the description of bioconjugates and nano drug carrier systems for diagnosis, imaging and therapy reported mainly in the last decade.