A dose-escalation study of daily etoposide and carboplatin was carried out on 23 patients with advanced lung cancer using a starting dose of 40 mg/m2/day etoposide given orally for 21 days and 250 mg/m2 carboplatin given intravenously (IV) on day 1. A total of 41 courses were given. Myelosuppression was the major dose-limiting toxicity. The maximum tolerated dose was reached at the fourth level with 40 mg/m2/day etoposide for 21 days and 400 mg/m2 carboplatin on day 1, once every 4 weeks. Non-hematological toxicities were generally mild or reversible. The recommended doses of this combination chemotherapy are 40 mg/m2/day etoposide for 21 days and 350 mg/m2 carboplatin on day 1. The response rate for non-small cell lung cancer and small cell lung cancer was 16.7% and 60% (95% confidence intervals of 3.6% to 41.4%, and 14.7% to 94.7%), respectively. A phase II study is necessary to define the efficacy and safety of this combination chemotherapy.