Dendritic cells (DCs) are professional antigen presenting cells (APCs). CD4⁺CD25⁺ T regulatory cells (T regs) are recognized as professional regulatory cells. DCs not only initiate T cell immunity by uptake, processing and presentation of specific antigens, but also induce immune tolerance by deletion of T cells and/or induction of regulatory T cells. CD4⁺CD25⁺ T regs maintain immune tolerance by suppressing the function of CD4⁺ and CD8⁺ T cells, B cells, macrophages, DCs and NK cells. It would be inconceivable that the delicate balance between immunity and tolerance could be kept impeccable without the crosstalk between DCs and CD4⁺CD25⁺ T regs. This review focuses on the recent development in our understanding of DCs and CD4⁺CD25⁺ T regs in immune tolerance, with transforming growth factor-beta (TGF-β) serving as a potential link between these two professionals.