The adenine nucleoside analogue fludarabine phosphate in combination with cytosine-arabinoside (Ara-C) and granulocyte-colony stimulating factor (G-CSF) has recently proved effective in the treatment of poor-prognosis acute non-lymphoid leukaemia. We used this triple combination in a case of Ph1+ chronic myeloid leukaemia (CML) unresponsive to alpha interferon that had progressed to acute phase after 5 months of treatment with 6-mercaptopurine plus hydroxyurea. The patient was treated with four courses of fludarabine 30 mg/m2 + Ara-C 2 g/m2 (days 1-5) and G-CSF (from day 0 to polymorphonuclear (PMN) recovery). Bone marrow blasts decreased from 80% to less than 5%, and karyotyping showed a progressive clearance of Ph1+ metaphases (from 100% to 9% after the fourth course). The patient is presently receiving autologous bone marrow transplantation (ABMT). This therapeutic success in a patient for whom conventional treatment would usually be ineffective makes this combination worthy of further studies, in view of its wider use as a preparative regimen to ABMT in CML.