The role of intensive induction chemotherapy in small cell cancer of the lung remains unclear. Twenty-eight newly diagnosed patients with small cell lung cancer were randomized to receive either high-dose or standard-dose cyclophosphamide, vincristine, and semustine in a trial where the dose of induction chemotherapy was the sole treatment variable. Complete responses (CR) were achieved in 57% of patients receiving high-dose therapy as compared to 21% of patients receiving standard-dose therapy (P less than 0.05). There was a higher rate of severe toxicity in the high-dose group (P less than 0.01). The overall median survival was not improved (36 weeks for the high-dose group vs 43 weeks for the standard-dose group); however, the median survival in patients achieving CR was prolonged (92 weeks for the high-dose group vs 50 weeks for the standard-dose group). These effects were most pronounced in patients with extensive disease; a CR after induction was achieved in five of nine patients treated with high doses but not in any of those treated with standard doses (P less than 0.05). A small group of patients appear to benefit by achieving a long-term remission with intensive induction chemotherapy, but this effect may be offset by increased morbidity.