Nano-engineered particles have been developed to reach specific molecular targets on diseased cells and have been used in various experimental and clinical conditions. The medical application involves diagnostic and therapeutic applications and a large deal of this research concerns malignant disease. Various approaches have been tried to effectively reach the cancer cell and PEGylated liposomes have demonstrated targeting and controlled release of antineoplastic drugs. For cancer diagnostics nanoparticles have been engineered to optimize magnetic resonance imaging, ultrasound imaging and nuclear medicine imaging. Radiolabeled nanoparticles can also be used for therapeutic purposes when tagged with appropriate radionuclides. This article aims to provide an overview how nanomedicine is presently influencing drug design and, more specifically, the development of radiopharmaceuticals for cancer management.