Increasing death toll globally due to cancer is the outcome of challenges not only in oncological disease detection but also in therapeutics. This led scientific community to explore the novel approach for cancer disease diagnosis and its treatment. Magnetic nanoparticles during the recent years in the field of cancer received considerable advancement, due to their certain properties which can be controlled by the various approaches of synthesis such as: hydrothermal, co-precipitation, thermal decomposition and polyol synthesis. However, significant increase in their biocompatibility can be achieved by the functionalization of NPs. Such tailored nanoparticles showed potential in enhanced imaging technology for cancer detection and therapies. Common core element, which is being used are silver, gold, etc. further usage of has been used as they harbour certain excellent qualities such as superparamagnetic and biodegradability. This chapter seeks to elaborate the unique properties of magnetic nanoparticles and their diagnostic and therapeutic implications in the field of cancer biology.