Essential thrombocythemia (ET) is a chronic myeloproliferative disorder characterised by the absence of the Philadelphia (Ph+) chromosome. Recent studies have reported controversial results relating to BCR-ABL rearrangements in ET patients. We studied 44 Ph-negative ET patients with the RT-PCR technique at diagnosis or during the follow-up. None of them showed any of the BCR-ABL transcript actually described by others in ET; neither the "classical" P210 nor the P190 or P230 variants. Our results confirm the absence of BCR-ABL abnormalities in Ph-negative ET patients.