The Myelo-Dysplastic Syndromes are a heterogeneous group of diseases which includes patients with different prognosis. There is no agreement about the management and the therapeutic strategy must be based on many individual parameters, particularly the age of the patients and their performance status. The therapeutic options range from no cytotoxic therapy for low-risk patients up to more aggressive treatment for high-risk patients, with disappointing results except for the very few cases eligible for allogenic bone marrow transplantation. The leukaemic cell can be induced to differentiate, so losing its self-maintenance potential; different drugs such as Interferon, vitamin D3, retinoids and arabinosyl-cytosine (low doses) have shown a differentiating action on myeloid blasts in "vitro". We summarize the general strategy in the treatment of myelo-dysplastic syndromes based on literature data, and on our results about the efficacy and tolerance of a combination of the above mentioned differentiating drugs, in a group of 27 elderly patients affected by myelodysplastic syndrome with poor prognosis. We obtained 14 objective responses (52%), and the median overall survival of these patients have been compared with that of 25 patients with severe myelodysplastic syndrome treated with a conventional regimen. In the 27 patients receiving the differentiating combination the median survival was found to be 14.7 months, versus 8.4 months for the control group. The results obtained are encouraging about the tolerance and the efficacy of this combination in elderly patients with a poor MDS prognosis. Further randomized studies are necessary to establish whether this treatment can really improve the survival in this group of patients.