Neuroblastoma is one of the commonest solid tumors in children. Conventional therapeutic approaches, such as surgery, chemotherapy and radiotherapy, fail to control tumor progression in stage III and IV patients. The search for novel therapeutic strategies should necessarily take into account immunotherapy and gene therapy. Here the theoretical bases for the development of such approaches are discussed. Studies carried out with neuroblastoma (NB) cell lines have shown that neoplastic cells express a wide array of potential tumor associated antigens (TAA) but are devoid of HLA molecules which are necessary for TAA presentation to the host immune system. Transfection of NB cells with the interferon gamma gene appears a promising approach, since this cytokine up-regulates the expression of class I HLA molecules in NB cells. Other cytokines of potential interest for gene transfer studies are interleukin 2 (IL2) and interleukin 12 (IL12).