Dendritic cells (DCs) are a heterogenous population of bone-marrow-derived immune cells. Although all DCs share a common ability to process and present antigen to naive T cells for the initiation of an immune response, they differ in surface markers, migratory patterns, localization, and cytokine production. DCs were originally considered to be myeloid cells, but recent findings have demonstrated that DCs can develop not only from myeloid- but also from lymphoid-committed progenitors. The common feature of the progenitors capable of developing into DCs is the surface expression of Flt3 receptor. The development of different populations of DCs is differentially regulated by various transcription factors and cytokines. This review summarizes the recent advances made in the field of DC development.