The immunogenic potential of renal cell carcinoma and the resistance of its metastases against chemotherapy, radiation and hormonal treatment have led to the development of a great number and variety of different strategies, summarized under the term immunotherapy. Objective remissions can be expected in about 20-40% of patients. Another 30-40% show stable disease for a limited time, only occasionally for longer. Most results are from uncontrolled phase II studies. A cancer cure can usually not be expected, long-term remissions are rare (5%), and high remission rates are only observed in studies with strong patient selection. Some authors have reported a higher survival rate in patients treated with IL-2 or IFN. Survival of patients with objective remissions is significantly improved. A standard therapy cannot be defined. Even presuming an increased survival rate, the toxicity, which can lead to a dramatic reduction in quality of life, and the high costs have to be considered carefully. We think that in view of the lack of therapeutic alternatives, the improving efficacy, the potential survival benefit, the reduction of toxicity and the perspectives, immunotherapy is essential in the treatment of metastatic renal cell carcinoma. Its use should be confined to clinical studies.