Five pulmonary function tests (transfer factor for carbon monoxide, diffusing capacity of the alveolar-capillary membrane, pulmonary capillary blood volume, alveolar volume, vital capacity) were performed, and creatinine clearance was measured in 39 patients with disseminated testicular nonseminomatous tumor treated with a combination chemotherapy containing bleomycin. Eight of these patients (20.5%) developed bleomycin-induced pneumonitis (BIP). To investigate which parameter has value in predicting BIP, a discriminant analysis was performed. The combination of a low normal creatinine clearance, a decrease in vital capacity and alveolar volume without a decrease in pulmonary capillary blood volume, pointed to an increased risk. We concluded that it is worthwhile to monitor these parameters and, if necessary, to adapt the chemotherapy of a patient at risk.