The prognosis of patients relapsing after an autologous transplant (autoSCT) is very poor. Allogenic stem cell transplantation (alloSCT) offers the possibility of curing some of these patients, at the cost, however, of a high transplant related mortality (TRM). The aim of this study was to analyze the outcome of 14 consecutive patients with hematologic malignancies, from a single institution, who underwent alloSCT for progressive disease after autoSCT. Patients had relapsed at a median of 11.5 months (range 2-72) after autoSCT and they underwent alloSCT at a median of 25.5 months (range 7-73) from the first transplant. Ten patients received HLA-identical related peripheral blood progenitor cells, three patients underwent matched-unrelated donor marrow transplants, and one patient received a mismatched related transplant. Conditioning regimens consisted of total body irradiation plus cyclophosphamide (n=5) or melphalan (n=1), or high-dose combination chemotherapy (n=8). Cyclosporin A and methotrexate were administered as graft-versus-host disease (GVHD) prophylaxis. Eight patients (57%) developed grade II-IV acute GVHD. All evaluable patients (n=6) presented extensive chronic GVHD. Overall survival at 1 year was 16% (median 3.5 months, 95% CI 0.7-10.3). Ten patients (71%) died from transplant related complications at a median of 3.5 months (range 0.7-11). Only one patient died of recurrent disease. Three patients remain alive and in complete remission at the time of this report (4, 20 and 20 months, respectively). In conclusion, alloSCT offers the possibility of a sustained control of the disease in some patients who relapse after an autoSCT. However, the procedure is associated with a high transplant-related mortality. Better results might be obtained by carefully selecting patients and by reducing the intensity of the preparative regimen.