The success of cancer immunotherapy depends on two major factors: adequate tumor-specific antigens and a vehicle capable of inducing a tumor-specific immune response by effective delivery of these antigens. Dendritic cells (DCs) are the most powerful antigen presenting cells, and because of their unique characteristics, these cells are actively used in cancer immunotherapy. In this review we describe recent data regarding different methods of loading these cells with tumor-associated antigens, including RNA or DNA transfer. We will discuss requirements for DC activation as pre-requisite for the success of cancer immunotherapy.