Nanoparticle-based theranostic agents combine diagnostic and therapeutic functions in a single nanosystem, offering potential for personalized medicine. These agents leverage the high capacity of nanoplatforms to deliver both imaging and therapeutic functions. Common nanomaterials include iron oxide nanoparticles (IONPs), quantum dots (QDs), gold nanoparticles (AuNPs), carbon nanotubes (CNTs), and silica nanoparticles (SiNPs). Each material has unique properties that enable imaging, drug delivery, and targeted therapy. IONPs are used for MRI and can be functionalized for drug or gene delivery. QDs offer bright, stable fluorescence for imaging and can be used for drug delivery. AuNPs are effective in photothermal therapy and can be functionalized for targeting. CNTs are used for imaging and drug delivery, while SiNPs provide a versatile platform for integrating multiple functions. Challenges include ensuring biocompatibility, long circulation times, and efficient targeting. Despite these challenges, nanoparticle-based theranostics are a promising area of research with significant potential for clinical applications.Nanoparticle-based theranostic agents combine diagnostic and therapeutic functions in a single nanosystem, offering potential for personalized medicine. These agents leverage the high capacity of nanoplatforms to deliver both imaging and therapeutic functions. Common nanomaterials include iron oxide nanoparticles (IONPs), quantum dots (QDs), gold nanoparticles (AuNPs), carbon nanotubes (CNTs), and silica nanoparticles (SiNPs). Each material has unique properties that enable imaging, drug delivery, and targeted therapy. IONPs are used for MRI and can be functionalized for drug or gene delivery. QDs offer bright, stable fluorescence for imaging and can be used for drug delivery. AuNPs are effective in photothermal therapy and can be functionalized for targeting. CNTs are used for imaging and drug delivery, while SiNPs provide a versatile platform for integrating multiple functions. Challenges include ensuring biocompatibility, long circulation times, and efficient targeting. Despite these challenges, nanoparticle-based theranostics are a promising area of research with significant potential for clinical applications.