A combined chemotherapy regimen comprising fludarabine, cytosine arabinoside, and granulocyte colony-stimulating factor (FLAG) has been used in the treatment of relapsed or refractory leukemias. We here report 38 patients with hematologic malignancies who underwent single-unit cord blood transplantation (CBT) with a conditioning regimen comprising 12-Gy total-body irradiation (TBI) and FLAG therapy (TBI/FLAG). Graft-versus-host disease (GVHD) prophylaxis consisted of tacrolimus or cyclosporin A and/or methotrexate. The median nucleated cell dose was 2.43 x 10(7)/kg (range: 1.96-3.55 x 10(7)/kg). Of 34 evaluable recipients, the cumulative incidence of donor engraftment was 97%. The median time to reach an absolute neutrophil count of 500/microL was 23 days (range: 18-35 days). The median time to an untransfused platelet count of 50,000/microL was 45.5 days (range: 28-208 days). Sixteen patients developed grades II-IV of acute GVHD. Fourteen patients were alive at a median follow-up of 46 months (range: 4-77 months). The estimated event-free survival at 3 years for all patients was 33.5%, with 72.7% in the standard-risk group (n = 11) and 17.7% in the high-risk group (n = 27) (P = .0075). These results showed that this novel regimen was well tolerated by patients and able to establish sustained donor cell engraftment, indicating the feasibility of TBI/FLAG as a conditioning regimen for CBT in adults with hematologic malignancies.