Allogeneic bone marrow transplantation from histocompatible sibling donors was performed in six patients with extranodal involvement of high grade lymphoma during first complete remission. Five patients had lymphoblastic lymphoma and one had diffuse undifferentiated lymphoma. The cytoreductive/immunosuppressive regimen consisted of total body irradiation and high dose cyclophosphamide. Four patients are alive in complete remission at 8 months, 14 months, 21 months and 47 months post transplantation. One patient who relapsed 7 months after his initial transplantation underwent a second transplantation but another relapse 17 months later led to his death. One patient died of chronic graft-versus-host disease and at autopsy there was no evidence of lymphoma. These data demonstrate that allogeneic bone marrow transplantation can produce durable remissions in patients with high grade lymphoma who present with bone marrow, central nervous system and/or skin involvement.