The aim of the present trial was to evaluate the effects of chemotherapy on the quality of life and survival of patients with advanced non-small cell lung cancer (NSCLC) (stage IIIB or IV). In a controlled multicentre trial, patients were randomised to receive supportive care only or supportive care plus chemotherapy. Chemotherapy consisted of intravenous (i.v.) carboplatin 300 mg/m2 on day 1 and etoposide 120 mg/m2 orally on days 1-5 every 4 weeks for a maximum of eight courses. Quality of life was measured at randomisation and prior to each treatment course and at corresponding 4-week intervals in the control arm, using the EORTC QLQ-C30 + LC13 questionnaire. 48 patients were randomised (supportive care 26, chemotherapy 22), being eligible for comparative analyses. Another 102 patients, 97 of which received chemotherapy, were subsequently included in the study on an individual treatment preference basis. Data from these patients were used for confirmative purposes. Patients in the chemotherapy group reported better overall physical functioning and symptom control compared with the supportive care group. Group differences were smaller within the psychosocial domain, although trends were seen in favour of the chemotherapy group. No significant differences were seen in favour of the supportive care group, except for hair loss. Median survival times were 29 weeks in the chemotherapy group versus 11 weeks in the supportive care group, and 1-year survival rates were 28% versus 8%. Quality of life and survival outcomes were similar in the randomised and non-randomised patients receiving chemotherapy. No treatment-related deaths occurred. In conclusion, treatment with carboplatin and etoposide can improve both the quality of life and the survival of patients with advanced NSCLC.