Myelodysplastic syndromes (MDS) are rare in children, representing 3% or less of all hematopoietic malignancies. Cytogenetic abnormalities, such as -7/7q-, +8, and +21 have been reported in 55-80% of children with MDS. Cytogenetic studies have an important impact on diagnosis, treatment selection, and monitoring therapeutic protocols when combined with morphologic data. We report on a pediatric case of MDS with the presence of the rare clonal abnormality del(13)(q14q22) which underwent a malignant transformation to leukemia and ran a very poor clinical course.