This book chapter discusses the use of functionalized magnetic nanomaterials (FMNs)Functionalized Magnetic Nanomaterials (FMNs) in biosensingBiosensing applications, particularly in detecting biomarkersBiomarkers, pathogens, and genetic material. FMNsFunctionalized Magnetic Nanomaterials (FMNs) are valued in biosensingBiosensing for their magnetic propertiesMagnetic properties and the ability to attach specific ligandsLigands for targeting. The chapter explores how FMNsFunctionalized Magnetic Nanomaterials (FMNs) interact with biological molecules, enabling accurate detectionTargeted detection in various biological samples. It also highlights the integration of FMNsFunctionalized Magnetic Nanomaterials (FMNs) into lab-on-a-chip devices for on-the-spot diagnosticsDiagnostics. These compact devices provide quick and cost-effective solutions for detecting biomolecules when needed, offering significant benefits in healthcare, environmental monitoringEnvironmental monitoring, and food safety. By examining recent progress and case studies, the chapter presents insights into the latest research and applications of FMNsFunctionalized Magnetic Nanomaterials (FMNs) in biosensingBiosensing. It addresses the challenges and future possibilities of incorporating FMNsFunctionalized Magnetic Nanomaterials (FMNs) into biosensingBiosensing platforms, underscoring their potential to transform diagnosticDiagnostics methods and advance personalized medicinePersonalization in medicine approaches.