In these last years the use of alpha-interferon (alpha-IFN) has received increasing attention especially in the onco-haematological field. alpha-IFN is particularly useful in the treatment of hairy cell leukemia, cryoglobulinemia, multiple myeloma and myeloproliferative syndromes (SMP). Among these latter conditions alpha-IFN must be considered as the treatment of choice of the early chronic phase of chronic myelogenous leukemia (LMC) in patients not eligible for allogenic bone marrow transplantation because its ability to induce a greater number of clinical remission and cytogenetic responses when compared to the classical chemotherapeutic agents. A myelosuppressive, non-leukemogenic effect and a more selective activity on the neoplastic hemopoiesis appear to be the most important advantages of alpha-IFN therapy. Based on the results obtained in LMC the use of alpha-IFN has been extended to the other SMP, essential thrombocytemia (TE), polycythemia vera (PV), idiopathic myelofibrosis with myeloid metaplasia (MMM). alpha-IFN is able to control thrombocytosis which often characterize the SMP so it appears to be particularly effective in TE. Actually a relatively limited literature is available about the alpha-IFN treatment of PV and MMM and so it is difficult to draw a final conclusion about the effectiveness of the treatment in these disorders. However, especially in PV, the use of this cytokine appears to be promising. The latest reports of the literature are here summarized and discussed.