We hypothesized that cyclophosphamide and cis-platinum, without adriamycin, which had been used in previous studies, may be equally efficacious, but less toxic. We treated 27 patients with non-small cell bronchogenic carcinoma with the combination of cyclophosphamide and cis-platinum. We report six responses (25% response rate), with median survival of 79 weeks as compared to 28 weeks in nonresponders (p less than 0.01). Our regimen had acceptable hematologic toxicity and tolerable gastrointestinal toxicity. However, cumulative nephrotoxicity and neurotoxicity were observed. We conclude that cyclophosphamide and cis-platinum may compare favorably to the cyclophosphamide, adriamycin and cis-platinum combination, with respect to response and toxicity.