In nanotechnology field, iron oxide magnetic nanoparticles (IONPs) have gained much interest. The magnetic nanoparticles have been widely explored for applications due to ease of manufacturing and functionalization with polymers and other materials which makes them highly sensitive for many biological and biomedical applications. They transform electromagnetic energy into heat when exposed to magnetic field, and, hence, prove themselves as potent anti-cancer agent. The most advanced application of nanoscale materials towards human health is application as contrast agents in imaging modalities. MNPs proved safer as imaging contrast agents than conventional methods. MNPs have also been used in overcoming bacterial resistance and as anti-viral agent. They provide further evidences as emerging means in treatment and diagnosis of CVD and chronic inflammatory diseases like Rheumatoid arthritis. They also have employed in gene therapy to treat chronic diseases now a day.