Personalized medicine has gained much attention as a major milestone in cancer treatment to overcome the underlying genetic variations in an individual's response to drug. Nanotheranostics have become a potential tool to overcome the critical challenges faced in personalized medicine development. In this perspective, iron oxide nanoparticles represent a potential class of nanomaterials attributing to their unique physicochemical properties for theranostic applications. This review summarizes the recent advances in the use of iron oxide nanoparticles (IONPs) in various applications such as magnetic resonance imaging (MRI), magnetically activated cell sorting, magnetic biosensors, magnetic hyperthermia, drug delivery, radioimmunotherapy, magnetofection and ferrotherapy in detail. © 2022 Elsevier B.V.