Bone marrow transplantation was performed between IV/82 and X/85 in 64 patients with acute leukemia (n = 36), chronic myelogenous leukemia (CML; n = 13), severe aplastic anemia (n = 12), and neuroblastoma stage IV (n = 3). Of these patients 57 received allogeneic marrow from HLA-ABCDR identical, MLC-negative sibling donors. Six transplants were performed with syngenic marrow and one with autologous marrow. Of the 64 patients 48 survived 40-1,250 days after transplantation, resulting in a survival rate (SR) of 75% and a survival probability (SP) of 71%. Of the 36 patients suffering from acute leukemia (SR = 64%, SP = 51%), patients with acute myelogenous leukemia (AML) in first complete remission (n = 11; SR = 81%, SP = 76%), as well as patients with acute lymphatic leukemia (ALL) in 1st to 4th complete remission at the time of transplantation (n = 14; SR = 81%, SP = 76%) show a favorable prognosis. A poor survival rate was seen for patients with AML when transplanted in second or partial remission (1/5; SR = 20%), as well as for patients suffering from ALL and transplanted during relapse or partial remission (1/6; SR = 16%). Of 13 patients suffering from CML 12 survived the transplantation free of relapse (SR = 93%, SP = 92%), and one patient died from varicella zoster pneumonia. Of the transplanted patients with severe aplastic anemia, 12 of 13 are surviving with complete hematologic reconstitution; one patient, however, died on day 10 from a sepsis. In our patient group, the SR as well as the SP has been improved through changes in the irradiation protocol concomitant with prophylactic application of anti-CMV hypergammaglobulin, as well as through additional oral medication of Azyklovir. The 41 patients (BMT No. 7-47) with total body irradiation at one time show an SR of 44% and an SP of 41%. The following 46 patients (BMT No. 48-93) have reached an SR of 83% and an SP of 74% under the regimen of fractionated total body irradiation, plus prophylaxis with anti-CMV hypergammaglobulin and Azyklovir. Within this group, no fatal CMV pneumonia was encountered as opposed to six patients lost from CMV pneumonia in the first group.