This study was designed to evaluate the efficacy of therapeutic intensification with autologous stem cell transplantation (ASCT) for mantle cell lymphomas (MCL) in terms of response rate, duration of response, and event-free and overall survivals. Twenty-four patients with confirmed MCL responding to chemotherapy received a high-dose chemo-radiotherapy regimen followed by ASCT. Transplantation was performed during first-line therapy in nine cases, second-line in 13 cases and third-line in two cases. The source of hematopoietic stem cells was peripheral blood for 19 cases. At the time of ASCT, eight patients were in complete remission (33%). Seventeen of the 24 cases received an intensified regimen with TBI and seven received the BEAM or the BEAC regimen. After transplantation, 19 patients were in CR (79%). Nine of these were alive in continued CR at a median follow-up of 34 months, while seven relapsed at a median of 18 months. One patient died from Pneumocystis carinii interstitial pneumonitis and five patients developed secondary malignancies. With a median follow-up after transplantation of 34 months, the 3-year event-free survival was 55% and the 3-year overall survival was 68%. These results indicate that therapeutic intensification with ASCT might be an effective treatment for mantle cell lymphomas. Bone Marrow Transplantation (2000) 25, 251-256.