The combination of carboplatin and etoposide is an active and well-tolerated regimen in the treatment of small cell lung cancer (SCLC). The aim of the study was to confirm whether the efficacy could be maintained if etoposide was administered orally. 106 consecutive, unselected, and untreated patients with SCLC (limited disease (LD) 44; extensive disease (ED) 62) were treated with a combination of carboplatin 300 mg/m2 intravenously (i.v.) day 1 and etoposide 240 mg/m2 orally days 1-3 every 4 weeks for six courses or until progression. If oral treatment was inconvenient, i.v. etoposide (120 mg/m2 days 1-3) was allowed. Thoracic irradiation (45 Gy in 22 fractions, split course) was given after three courses of chemotherapy to 29 patients with LD. Objective response (complete and partial) was seen in 89% (confidence interval (CI) 75-97) of patients with LD and in 53% (CI 40-66) with ED. Complete response was seen in 41% (CI 26-57) of patients with LD and in 8% (CI 2-18) with ED. Median time to progression for responders was 11 months and 6 months for patients with LD and ED, respectively. Corresponding median survival was 15 months (range 1-45 months) and 8.5 months (0-26 months). Myelosuppression comprised the main toxicity. Leucopenia (WHO III-IV) was observed in 20% and thrombocytopenia (WHO III-IV) in 16% of the cases. One patient died of sepsis during leucopenia. Oral treatment was convenient for most patients and therapy well tolerated. However, 9 patients (20%; CI 9-36%) with LD and 26 patients (42%; CI 29-56%) with ED received at least part of the etoposide treatment i.v.. The present study shows that the combination of carboplatin and oral etoposide is active and well tolerated, and may be used on an outpatient basis in patients with small cell lung cancer.