Using a nonmyeloablative, immunosuppressive, fludarabine (FLU)-base conditioning regimen, we have performed allogeneic peripheral blood stem cell transplants in 17 patients (six with chronic granulocytic leukemia, four with acute myelogenous leukemia, five with acute lymphoblastic leukemia, one with myelodysplasia and one, with thalassemia major). Conditioning regimen consisted of FLU/busulfan/cyclophosphamide or FLU melphalan. To avoid graft vs. host disease (GVHD), cyclosporine and methotrexate were used. Median granulocyte recovery time to 0.5 x 10(9) was 11 days, whereas median platelet recovery time to 20 x 10(9) was 12 days. Seven patients did not need red blood cell transfusions and four did not need platelet transfusions. In thirteen individuals (76%), the procedure could be completed fully on an outpatient basis. Follow-up times range between 1 and 14 months. Five of 17 patients developed acute GVHD whereas 4/10 developed chronic GVHD. The 14-month survival (SV) is 70% and median SV is not reached. Five patients (29%) have died, three due to relapse of the disease and two due to GVHD. The transplant-related mortality was 5.8%. This procedure is substantially less costly than its counterpart, using in-hospital myeloablative conditioning regimens, and may represent another approach in management of patients requiring allogeneic stem cell transplant.