Myelodisplastic syndromes (MDS) in childhood deserve a negative prognosis even though disease-free survival has been obtained in 20% of cases by using aggressive chemotherapy. We describe three children with refractory anemia with excess of blasts in transformation (RAEB-T) who underwent bone marrow transplantation (BMT). We also reviewed 21 additional cases (median age was 8 years) with primary MDS recently reported in the literature with the aim of clarifying the role of BMT in treating these patients. Twelve of the 24 children were long-term survivors and free from disease at a median time of 1,320 days (range 302-2,340). There were five relapses, two graft failures, two early deaths (one VOD, one severe GVHD), and three late deaths (two respiratory diseases, one severe GVHD). We didn't find any correlation between karyotype and outcome. In conclusion, so far BMT seems to be the most valid treatment of childhood primary MDS. However, since the major causes of failure were regimen-related toxicity or recurrence of the disease after BMT, it must be pointed out that, when a compatible donor even unrelated is available, BMT for childhood MDS should be given as soon as possible or at any rate prior to blastic crisis.