Recently, there has been an increase in the types of biological therapeutic approaches developed for the treatment of cancer. This rapid advance in the biological therapy of cancer is due in part to advances in the field of molecular and cell biology as well as in the development of gene transfer systems. In particular, a better understanding of the mechanism of antigen presentation and T lymphocyte activation has resulted in the development of new immunotherapeutic strategies targeting tumor-associated antigens (TAA). The discovery of dendritic cells (DC) as potent antigen presenting cells and the development of methods for their use in immunotherapeutic regimens has led to novel approaches for treating cancer. Furthermore, the identification of genes encoding TAA and their peptide products, which are recognized by T lymphocytes in the context of major histocompatibility complexes class I and class II molecules, has led to the development of DNA-based vaccines against defined tumor antigens. Cytokines have been shown to be important adjuvant tools for immunization protocols by directing a T helper response favorable for an adequate cytotoxic T lymphocyte-mediated immune response. Novel gene transfer technologies have made it possible to employ a wide range of gene delivery systems, either viral or nonviral based, in anticancer therapies. Current immunotherapeutic strategies, including the use of DC transduced with genes coding for tumor antigens and cytokines delivered by recombinant viral vectors, have shown promise in animal tumor models.