The transcription factor CEBPA is crucial for normal myeloid differentiation. CEBPA gene mutations have been reported in patients with acute myeloid leukaemia. The inevitable evolution of chronic myeloid leukaemia (CML) in chronic phase (CP) to a fatal blast crisis (BC) is assumed to result from the acquisition of additional genetic changes in the leukaemic clone. Gain of CEBPA mutations might represent a key event causing the differentiation block observed in myeloid CML-BC, but not in CML-CP. Here, no CEBPA mutation in 95 CML-BC patients was found, suggesting a limited role, if any, of CEBPA mutations in this disorder.