Dendrimers represent a class of polymers characterised by their well-defined structure, with a high degree of molecular uniformity and low polydispersity. They have found a wide-range of pharmaceutical applications; however, more recently, they have been shown to function as effective intracellular carriers for drugs. In addition, dendrimers have been shown to be capable of bypassing efflux transporters. A new generation of dendrimer-based delivery systems will enable the efficient transport of drugs across cellular barriers.