A growing list of defined tumor-antigens opens the way to antigen specific immunotherapy of cancer. However current approaches are often limited in their potential to induce an effective anti-tumor response. Dendritic cells (DC) are natural adjuvants for the induction of antigen specific T cell response. They have been successfully used in clinical pilot trials to induce tumor specific immunity as well as clinical response in selected patients. Current research focuses on optimization of DC source, choice of antigen, antigen loading, mode of injection, as well as immuno-monitoring. Finally, a variety of immune escape mechanisms are operative at the tumor site and have to be overcome for successful vaccination.