Very interesting case in which a CML responding well to IFN therapy is associated with an MDS with a complex karyotype. Although some data are missing to calculate R-IPSS precisely, the patient should fall into the poor or very poor risk category and therefore considering the risk, the age and the possible availability of a sibling donor, if no other contraindications are present, I would switch the patient to SCT (also UBMT if the sister is not compatible). The 5q- abnormality could support the use of lenalidomide, although the complex caryotype decreases the probability of a good response to this therapy. Finally the option of some cycles with Azacytidine has to be considered, in particular as a preparative regimen to induce remission in view of the transplant procedure. The problem of this patient is not CML, but MDS and this is not due to IFN or CML, but probably to environmental or occupational exposure to genotoxic agents that were likely to be the cause for both, MDS and CML.