Patients with either relapsed or refractory T-cell acute lymphocytic leukemia (T-ALL) are candidates for allogeneic hematopoietic stem cell transplantation (allo-HSCT). Achieving complete remission (CR) in these patients is difficult but crucial for the success of allo-HSCT. In this study, we examined 6 relapsed or refractory T-ALL patients. In the patient group, 4 were male and 2 were female, with ages ranging from 15 to 57 years (median = 29 years). All 6 patients presented with the nonmature T-ALL phenotype. Cytogenetically, only one had an i(7q) anomaly, whereas the remaining 5 cases had normal karyotypes. One of these patients had the MLL/AF9 fusion transcript, as shown by molecular study. After initial remission-induction therapy, two patients achieved CR, one showed a partial remission, and all relapsed soon. The other 3 cases failed the therapy. The CAG regimen (cytosine arabinoside 10 mg/m2 subcutaneously every 12 hr, day 1–14; aclarubicin 5–7 mg/m2 intravenously daily, day 1–8; and concurrent use of G-CSF 200 μg/m2/day subcutaneously) was devised originally for the treatment of relapsed acute myelogenous leukemia. After CAG therapy, all the T-ALL patients in our study achieved CR, indicating that the CAG regimen is beneficial to the treatment of relapsed or refractory T-ALL. The efficacy of CR-induction in T-ALL patients and the adverse effects of the CAG regimen need to be further studied. Am. J. Hematol., 2008. © 2007 Wiley-Liss, Inc.