Fourteen patients with extensive disease small cell bronchogenic carcinoma (SCBC) received ifosfamide at 2,000 mg/m2/day for 5 consecutive days with simultaneous mesna and vincristine while 26 patients with extensive disease non-small-cell bronchogenic carcinoma (N-SCBC) received the same regimen without vincristine. Eight partial responses (57%) were observed with a 40-week median survival in the case of SCBC and four partial remissions (15%) with a 31-week median survival in N-SCBC. Granulocytopenia was the dose-limiting toxicity, whereas urotoxicity was well controlled with mesna. Neuropsychiatric toxicity consisted of anxiety, agitation, confusion, and hallucination. Neurobehavioral testing detected worsened performance during ifosfamide treatment. Ifosfamide is one of the few active agents in N-SCBC.