Our insight into antitumour immune responses has increased considerably during the past decades, yet the development of immunotherapy as a treatment modality for cancer has been hampered by several factors. These include difficulties in the selection of the optimal dose and schedule, the methods of evaluation, and financial support. Although durable clinical remissions have been observed with various immunotherapeutic strategies, the percentage of patients who benefited from these interventions has remained too small to justify the general use of such strategies. However, the recent positive results of clinical trials with novel immunoactive drugs as well as the unexpected finding of a positive interaction between immunotherapy and chemotherapy may herald a new era for the immunotherapy of cancer.