Increases in both life expectancy and cancer incidence with age result in a significant rise in lung cancer rates among elderly patients, with a median age at diagnosis of between 63 and 70 years. However, elderly patients are under-represented in clinical trials and generally receive suboptimal treatment, mainly because of fears about increased toxicity of chemotherapy. Indeed, physiological modification of renal and haematopoietic functions with age together with co-morbidity and associated polypharmacy may alter the metabolism of chemotherapy drugs, resulting in greater toxicity. Moreover, performance status (PS), the main prognostic factor in younger patients, does not correlate well with geriatric indexes such as activities of daily living, cognition and physical performance, and comprehensive geriatric assessment is important in elderly patients.