Late occurrence of radiation-induced pulmonary pneumonitis and fibrosis is well documented. We report an unusual case of radiation induced veno-occlusive disease (VOD) occurring six years following mantle irradiation for Hodgkin's lymphoma. The patient developed severe pulmonary hypertension and cor pulmonale. A left lung transplantation was performed successfully and pathologic examination of the explanted lung showed severe changes compatible with VOD. In the absence of exposure to alternate therapeutic or toxic agents that may cause VOD, it is likely that radiation caused damage to the venular endothelium and caused progressive obliteration of the pulmonary vessels. Review of the literature reveals only a few similar reports of VOD mostly following radiation for bone marrow transplantation. We conclude that previous irradiation (even several years earlier) should be considered as a possible cause of pulmonary VOD.