Nanotechnology has revolutionized modern medical diagnostics by enabling highly sensitive, specific, and rapid detection of diseases at early stages. The integration of nanomaterials such as quantum dots, gold nanoparticles, and carbon nanotubes into diagnostic platforms has improved imaging techniques, biosensing, and lab-on-a-chip devices. This article explores the advancements in nanotechnology-based diagnostics, including applications in cancer detection, infectious disease diagnosis, and point-of-care testing. Additionally, challenges and future prospects are discussed to highlight the potential of nanotechnology in transforming healthcare diagnostics.