This chapter aims to show state-of-the-art transd ermal drug-delivery nanocarriers. The advances in this field are very important at present because the skin offe rs many advantages over othe r organs due to its size. Depending on the location, we can deliver drugs very close to the target area. The skin provides protection against microorganisms, temperature, mechanical factors, etc. [1-3]. The development of submicron particles and other nanostructures in the pharmaceutical and cosmetic fields has been employed for the design of formulations for application through the skin [4-7]. The mechanism by which submicron particles traverse the skin is interesting and important as well as size and composition. The nature of drugs that can be applied through the skin offers many possibilities for future therapies. Both lipophilic and hydrophilic compounds can be used for this purpose, depending on the chosen nanocarrier. Finally, rega rding the specific applications of nanocarriers, it is worth mentioning that scientists have used nanocarriers for several applicat ions, including delivery of local and systemic therapies.