We examined whether cisplatin-induced nephrotoxicity augmented bleomycin-induced pulmonary toxicity in patients with testicular cancer treated with etoposide and cisplatin with (BEP) or without bleomycin (EP). Before and at 3-week intervals during chemotherapy, creatinine clearance and lung functions were measured. In patients receiving BEP, deterioration of renal function correlated with a decrease in transfer factor of the lungs for carbon monoxide (TLCO) and vital capacity (VC), parameters known to reflect bleomycin-induced pulmonary effects. Other lung functions did not correlate with renal function. In the EP group, no relationships were observed at all. These observations suggest enhanced pulmonary effects of bleomycin when combined with cisplatin. Therefore, attention should be paid to the potential development of bleomycin-induced pulmonary toxicity in patients treated with BEP.