This study concerns the clinical applications in Oncology of Biologic Response Modifiers; the authors focus the results reached in neoplasms, such as renal cell carcinoma or melanoma, whose sensitivity to this treatment has been proved. Prospective studies, published in 1990 have been reviewed, considering only those in which route and rate of response (complete and partial) were clearly specified. At present clinical efficacy concerning this topic is controversial and it probably depends on different reasons: immunogenicity of cancer, variable route of administration, lack of predictors. It should be stressed that more in depth studies about cancer immunology are required; a wide spread of immunotherapy will be feasible only by improving therapeutic strategies and limiting adverse effects of this treatment.