We report a 25-year-old woman with T-cell large granular lymphocytic leukaemia presenting with severe neutropenia, anaemia and recurrent infections with a chronic disease course. Immunophenotyping showed an expansion of CD3;<sup>+</sup>, TCRγδ<sup>+</sup>, CD4<sup>-</sup>, CD5;<sup>+</sup>, CD7;<sup>+</sup>, CD8;<sup>+</sup>, CD57;<sup>+</sup> large granular lymphocytes. Clonality was demonstrated with T-gamma polymerase chain reaction analysis which revealed clonal rearrangement of the TCRγ chain gene. Cyclosporine, granulocyte colony-stimulating factor, methothrexate and a combination of cyclophosphamide, vincristine and prednisolone failed to correct the neutropenia and the anaemia. Finally, treatment with 2-deoxycoformycin resulted in both clinical and haemotological complete responses, despite molecular evidence of the persistence of the abnormal T-cell clone.