The quality of life of lung cancer patients is affected by several factors related to the patients, stage of disease and treatment characteristics. For small-cell lung cancer (SCLC), the treatment is generally aggressive, primarily based on chemotherapy. Treatment strategy for non-small-cell lung cancer (NSCLC) is strongly dependent on the stage of the disease and ranges from surgery to palliative chemotherapy. Over the last few years, very little progress has been made in terms of survival. Therefore, the effect of treatment on quality of life has become progressively more relevant. Among the instruments for measuring quality of life, there are some specifically developed for lung cancer, such as the European Organization for Research and Treatment of Cancer (EORTC) LC-13 questionnaire, the Functional Assessment of Cancer Therapy (FACT-L) questionnaire and the Lung Cancer Symptom Scale (LCSS). Up to now, few randomised clinical trials have correctly evaluated quality of life. There are evident pitfalls associated with the use of frequently non-validated tools, and poor methods of data analysis, but quality-of-life evaluation is crucial and should be addressed through well-planned and well-conducted prospective clinical trials.