Over the past few decades, nanomaterialsNanomaterials have been extensively used in various fields, especially in biomedicine and healthcare. Their unique physicochemical properties, such as high surface area and nanoscale size, make them highly desirable. Recently, there has been significant interest in developing therapies based on magnetic nanoparticlesMagnetic nanoparticles for biomedical applicationsBiomedical applications, owing to their unique advantages. Magnetic particles, which respond to magnetic forces, are useful in drug targeting and bioseparation, including cell sorting. To be used in biomedicine, these magnetic nanomaterialsMagnetic nanomaterials often need to be modified or functionalized with other materials. This functionalizationFunctionalization allows them to be used in various biomedical applicationsBiomedical applications, such as biosensingBiosensing, drug deliveryDrug delivery, imagingImaging, medical implantsMedical implants, cancer treatmentCancer treatment, antibacterial and antiviral applicationsAntiviral applications, and tissue engineering. Additionally, functionalized magnetic nanomaterials (FMNsFunctionalized Magnetic Nanomaterials (FMNs)) have applications in hyperthermic treatments. For instance, magnetite nanoparticles conjugated with antibodiesAntibodies, known as antibodyAntibodies-conjugated magneto-liposomesMagneto-liposomes (AMLs), are used in hyperthermiaHyperthermia and enhance tumor-specific contrast in MRI via systemic administration. This chapter provides a critical overview of recent research on functionalized magnetic nanomaterialsFunctionalized Magnetic Nanomaterials (FMNs) in biomedical applicationsBiomedical applications. It also discusses the role of the magnetic propertiesMagnetic properties of these nanomaterialsNanomaterials in targeted therapeutic approaches and improved diagnosticDiagnostics tools.