Layered double hydroxides (LDHs), well known as anionic or hydrotalcite-like clays consist of positively charged layers and exchangeable anions along with water molecules in the interlayer space. Due to excellent characteristics including lamellar structure with nanosized interlayer space, positive charge on layers; absorption, storing, carrying and release ability of anions; simple inexpensive synthesis routes and memory effect along with low or null toxicity and good biocompatibility; these bioceramics have gain a great deal of attention in biological and medical applications. Recently, applications such as drug and gene delivery systems have been reviewed in various articles. Moreover, intercalation of biomolecules and contrast agent materials in the interlayer space of LDHs has been shown to be promising in novel diagnostic systems such as biosensors and medical imaging. In this article the role of LDHs in these medical applications is reviewed.