The quality of life of patients treated with radiotherapy and chemotherapy for non-small cell lung cancer is compared in a randomized study. A standardized questionnaire composed of 12 questions covering psychosocial well-being (10 question index), and global quality of life evaluation (2 questions) was used to evaluate the patient's quality of life. Data were collected before treatment was started and at 7 different occasions up to 52 weeks after the beginning of the first treatment. The psychosocial well-being index and the 2 global questions were found to have a high degree of validity in a previous study. Two weeks after the start of treatment, the psychosocial well-being index for patients receiving radiotherapy was significantly higher than for patients treated by cytostatic drugs. This observation was confirmed by the 2 global questions. No differences in the quality of life were detected in the follow-up period (6-52 weeks).