This chapter will focus on the methods of synthesis of phosphorus-containing dendritic architectures, mainly of phosphorhydrazone type, coming from our group, but also on other types of phosphorus dendrimers coming from other laboratories. The different types of cores, branches, and surface functionalities of phosphorhydrazone dendrimers will be displayed. An overview of the field will be given, concerning not only regular dendrimers, but also dendrimers with layered architectures, dendrons, and various types of less symmetrical dendritic architectures, all based on phosphorus derivatives. The properties of these compounds will be briefly highlighted in the last part of this chapter, concerning in particular catalysis, nanomaterials, and biology/nanomedicine.