As a facultative intracellular bacterium,Listeria monocytogeneshas adapted to live within the cytosol of the host cell. It is actively taken up by antigen-presenting cells through phagocytosis, and asListeriasurvive within these cells, it is an ideal vector for the delivery of antigens to be processed and presented through both the class I and II antigen-processing pathways. Once phagocytosed,Listeriaproduces virulence factors within the phagolysosome of the host cell, which allows it to break out of this organelle and live in the host cytosol. It is possible that these virulence factors can enhance the immunogenicity of tumor-associated antigens, which are poorly immunogenic. Recent progress in the development of this bacterium as a vaccine vector for tumor-associated antigens is discussed in the context of bacterial vectors in general. In several mouse models,Listeria-based vaccines have been demonstrated to be an effective method of influencing tumor growth and eliciting potent antitumor immune responses. Safety issues and the transition ofListeriainto human clinical trials will also be discussed in this review.