Carboplatin, a second generation platinum complex, is less nephrotoxic and emetogenic than its parent compound. We have tested the objective response to and the toxicity of the combination carboplatin 330 mg m-2 on day 1 with etoposide 120 mg m-2 on days 1, 3 and 5, administered every 3 weeks in histologically proven inoperable non-small-cell lung cancer (NSCLC) patients with a good performance status. Thirty-one patients entered the study; 29 were evaluable for response, 24 after 3 courses and 5 after 2 courses of chemotherapy. An overall response rate of 21% was found including zero complete response and 6 partial responses. In addition, 3 minor responses (10%), 12 stable diseases (38%), and 9 progressive diseases (39%) were observed. The median survival was 48 weeks, including 68 weeks for non-metastatic (M0) patients and 27 weeks for metastatic (M+) patients. This regimen was well tolerated. Gastrointestinal toxicity never exceeded WHO grade II and renal function remained in the normal range for all cases. Haematological toxicity was low in the majority of the cases; nevertheless it proved to be the dose limiting toxicity as illustrated by two grade III anemia, one grade III leucopenia, one grade III and one grade IV thrombocytopenia. Carboplatin-etoposide combination is not more active, but clearly much less toxic than cisplatin-etoposide in NSCLC.