From 1978 to 1981, 537 patients with advanced non-small cell lung cancer were randomly assigned to three regimens containing cyclophosphamide and doxorubicin alone or in combination with methotrexate or cisplatin. Eligible patients had measurable disease and had no prior exposure to chemotherapy. Of the patients entered on the study, 505 were evaluable for toxicity and 488 were evaluable for response. The overall response rate (complete and partial responses) was only 9%. Response rates did not vary significantly with respect to treatment regimen, histologic subtypes, extent of disease, or performance status. There was no survival advantage for any regimen. The major toxicities were myelosuppression and nausea-vomiting. These doxorubicin-based chemotherapy regimens produced disappointing results in patients with advanced non-small cell lung cancer. A search for more active antitumor agents in lung cancer is necessary.