Dendritic cells (DCs) initiate and regulate immune responses. Numerous studies in mice showed that tumor antigens-loaded DCs are able to induce therapeutic and protective anti-tumor immunity. The immunogenicity of antigens delivered on DCs has now been demonstrated in cancer patients and some clinical responses without any significant toxicity have been observed. Nevertheless, many parameters of DC vaccination need to be established including: (1) the type of DCs, their maturation stage and stimuli; (2) the quality and the breadth of induced immune responses; (3) host-related factors, such as the extent of metastatic disease and myeloablation; and (4) efficacy as measured by the clinical outcome.