[en] Purpose: To retrospectively compare the acute and long-term pulmonary toxicities of total body irradiation and busulfan in bone marrow transplantation. Methods and Materials: From March 1984 through February 1991, 144 patients received high-dose therapy with cyclophosphamide plus either total body irradiation (TBI-CY) or busulfan (BU-CY) followed by bone marrow rescue. Treatment protocols were based on disease type. Cyclophosphamide dose was 120-200 mg/kg, given in 2-4 days. Total body irradiation was given as 12 Gy in four fractions over 4 days, or 14.4 Gy in eight fractions over 4 days. Busulfan dose was 16 mg/kg given over 4 days. Results: Seventy-nine patients were treated with TBI-CY and 65 patients with BU-CY. More patients in the TBI group had allogeneic transplants (40 vs. 18). Pulmonary events occurred in 48 patients, 19 in BU-CY and 29 in TBI-CY. Of the 58 patients with allogeneic transplants, 21 (36%) developed chronic graft-vs.-host disease (GVHD), and 10 of those patients developed pulmonary complications (including 2 with obliterative bronchitis and 1 with asthma). Interstitial pneumonitis (IP) occurred in 14 patients, 12 in the TBI-CY group and 2 in the BU-CY group. Cytomegalovirus and pneumocystis infections were associated with IP in 11 of those patients. Fatal idiopathic IP occurred in one patient in each of the TBI-CY and BU-CY groups. Multivariate analysis showed that only chronic GVHD and prior bleomycin use were significant predictors of interstitial pneumonitis; no difference was seen between TBI-CY and BU-CY. Conclusions: Pulmonary complications were most commonly associated with GVHD and prior bleomycin use. The incidence of cytomegalovirus or pneumocystis carinii pneumonitis was greater in the patients receiving the TBI regimen; fatal pulmonary complications were not significantly different between TBI and nonTBI regimens