A controlled clinical trial comparing combination chemotherapy was performed in 147 patients with advanced inoperable non-oat cell bronchogenic carcinoma. All patients were stratified according to cell type, performance status, and extent of disease. They were then randomized to one of two combination treatment regimens selected by cell type. In epidermoid carcinoma, the combination of CCNU, methotrexate, and adriamycin was found to be more effective than 5-fluorouracil and procarbazine both in terms of objective response rate (19% vs. 0%) and survival. Two patients (4%), one with extensive disease, are alive in complete remission for 424+ and 540+ days. In adenocarcinoma of the lung the combination of CCNU, cyclophosphamide, and methotrexate was more effective than 5-fluorouracil and adriamycin with objective response of 25% vs. 15% and improved median survival. Neither the combination of cyclophosphamide and adriamycin, or the combination of CCNU, procarbazine, and 5-fluorouracil had demonstrable activity in large cell carcinoma of the lung. Responders, both objective responders and stable responders, lived longer than patients with progressive disease among all histological types. The achievement of a complete remission appears to be necessary for significant survival prolongation in epidermoid carcinoma. Previous treatment did not influence response or survival. Extent of disease and performance status in addition to cell type influenced response and survival and patients with advanced lung cancer should be stratified according to these variables. Patients who were 250% bedridden rarely responded to treatment and had a significantly (p < .005) shorter survival.