Our aim was to study the extent of pulmonary toxicity after high-dose chemotherapy and radiotherapy in breast cancer patients. In a retrospective study the pulmonary symptoms and chest X-rays were analyzed before, during and after treatment in 17 patients, treated with loco-regional radiotherapy to the breast/chest wall and the regional lymph nodes after the completion of high-dose chemotherapy and autologous bone marrow transplantation for locally advanced breast cancer. Lung function was evaluated between 15 and 46 months after completion of the irradiation. Nine patients (53%) had pulmonary symptoms during and/or within two months from irradiation. Radiographic changes were seen in twelve patients (71%) and a decreased diffusion capacity occurred in nine patients (53%). The spirometric values (VC and FEV1) were abnormal in two patients (12%). There is a high incidence of radiation pneumonitis, although no consistent correlation between the various parameters (pulmonary symptoms, chest X-rays and lung function tests) could be found.