The therapeutic efficacy of interferon-alpha (IFN-alpha) in the treatment of chronic myeloid leukemia is currently being tested in a number of institutional, interinstitutional, and international trials. There is no doubt that responses are achieved in many patients, and in a small subset complete eradication of clonogenic cells may be possible. However, it has not yet been shown that overall survival of patients treated with IFN-alpha is better than that of those treated with conventional cytoreductive drugs. There are still controversial opinions on problems such as dosages and duration of treatment, combination with cytostatic agents, definition of responses, and relevance of cytogenic and molecular data. An international workshop discussed the data on interferon therapy and attempted to define the role of interferon today in the management of chronic myeloid leukemia.