BACKGROUND Allogeneic bone marrow transplantation (BMT) is the only potentially curative treatment in multiple myeloma (MM). METHODS From january 1986 to december 1993, 12 cases (10 males and 2 females) underwent BMT in the authors' institution. The mean age of the series was 39 years (range 23-49). The situation of the myeloma on initiation of the conditioning was: complete remission (CR) in 2 cases, objective response in 5 cases, partial response in 1 case and treatment resistance in 4 cases. The conditioning schedule included cyclophosphamide (120 mg/kg) and total body irradiation (10-14 Gy) with or without melfalan at high doses in 11 patients and busulfan (16 mg/kg) and cyclophosphamide (120 mg/kg) in 1 case. The prophylaxis of graft versus host disease (GVHD) was carried out with methotrexate and cyclosporine A (CsA) in 7 cases, CsA plus prednisone in 2 cases and 3 patients received CsA plus bone marrow partially depleted of T lymphocytes by elutriation. RESULTS The situation of the myeloma with regard to response following transplantation was: unevaluable in 1 case, resistant in 1 case, objective response in 2 cases and CR in 8 cases. Seven out of the 10 patients at risk presented grades II-IV GVHD. Four of the 8 patients who were in CR following transplantation died due to post transplant complications and 2 out of the 6 relapsed 9 months after the transplant while 2 remain in CR at 5 and 8 years after the transplant, respectively. Nine patients died due to infection in 2 cases, GVHD and infection in 4 cases, GVHD and hemorrhage in 1 case and progression and infection in 2 cases. Of the 3 surviving patients, 1 relapsed at 14 months after the transplant and two remain in CR at 5 and 8 years post transplantation. CONCLUSIONS Bone marrow transplantation conditioning gives place to a high number of complete remission in multiple myeloma. However, the incidence of acute grade II-IV graft versus host disease and mortality due to complications related to the transplantation are very high. Nonetheless, a proportion of patients may achieve curation with bone marrow transplantation.