Dendrimers are a class of macromolecular materials with a highly branched three-dimensional structure. Since its inception in 1978, the dendrimers have attracted much attention for their biomedical applications. Structurally, dendrimers can be divided into three components: the core, the interior and the shell. The stepwise growth technique gives rise to nearly monodisperse polymeric tree-like macromolecules, which are essential for biological applications, since the monodispersity is a key factor for generation of reproducible structure that allows evaluation of the biological activity relating to specific structures. In addition, the reactive functional groups on the exterior give provision to modify its outer surface so as to achieve multivalent effects, such as improved pharmacokinetics, combined drug delivery, site specific delivery of therapeutics using targeting molecules, reduced cytotoxicity and limited long-term side effects. This chapter presents a basic concept of this evolving technology and explores the unique features of this nanomaterial for successful future applications as biotherapeutics.