In recent years, medicinal chemists have begun to realize that dendrimers may be a keystone in the future of medicine. The field of oncology will soon be revolutionized by novel strategies for diagnosis and therapy employing dendrimer-based nanodevices. In the near future, cancer diagnosis via MRI will be improved by the incorporation of dendrimers as advanced contrast agents. Novel dendrimer-based contrast agents can not only be targeted specifically to cancer cells but may also incorporate a cytotoxic function to induce apoptosis on said cells as well. Dendrimers are being applied to a variety of cancer therapies to improve the safety and effectiveness of many common therapeutics. Investigations into the applicability of dendrimers in photodynamic therapy, boron neutron capture therapy, and gene transfection are also being undertaken. This review will cover the fundamentals of cutting-edge research utilizing dendrimers for cancer diagnosis and therapy. An objective review of these new technologies will detail how dendrimer-based nanodevices are advantageous over conventional medicine.