The presence of acquired clonal cytogenetic abnormalities in hematopoietic cells is one of the diagnostic hallmarks of myelodysplastic syndromes (MDS). Such anomalies may help in defining prognostic groups. We analyzed eight pediatric MDS, and herein describe three new cases, one de novo and two therapy-related, presenting an unbalanced rearrangement of 1q: one of them resulted in a derivative chromosome 6 apparently identical to a previously described one. We also review all the cases of gain of 1q reported in de novo and therapy-related childhood MDS.