Nanoclays are layered silicate nanostructures that exist in various types and morphologies and their application in medicine dates back to ancient times. Their impressive properties such as large surface area, biocompatibility, cation exchange property, high capacity for intercalation of various compounds, reasonable price, and facility of their surface modification and functionalization make them compatible with a wide range of different compounds. These properties have led to their application in nanomedicine and clinical diagnostics as two major fields of biomedicine. Nanoclays have been extensively used in a variety of medical fields. They are employed in sensor fabrication as matrices for immobilizing recognition elements like enzymes and probes such as fluorescent dyes. Additionally, nanoclays contribute to enhancing the conductivity of electrodes, showcasing their versatility and impact on medical diagnostics. Furthermore, nanoclays are promising nanomaterials for designing drug delivery systems with enhanced efficiency, biocompatibility, and controlled release of pharmaceuticals and bioimaging agents. Additionally, they have been extensively used in tissue engineering for the achievement of reinforced and natural mimicking scaffolds, especially in bone tissue engineering. Considering the great applications of nanoclay in biomedicine, the present chapter introduces the most common nanoclays and various approaches for modification and functionalization of them. Additionally, the recent applications of various nanoclays in the biomedical fields will be reviewed in this chapter.