Quality of life (QOL) is an important consideration in the treatment of patients with advanced lung cancer because treatment is largely palliative. Moreover, QOL predicts survival in non-small cell lung cancer, and there is increasing acceptance by clinicians and regulatory authorities of symptoms and QOL as primary or coprimary endpoints in clinical trials. This article reviews the signs and symptoms of advanced lung cancer that commonly affect QOL, and the prevalence, emergence, and decline of symptoms in patients with good performance status during and after treatment. Next, it details the various tools for measuring QOL in patients with lung cancer and data that support the use of QOL data to guide individual treatment decisions. Finally, it discusses the need for a better understanding of the QOL and treatment preferences of patients with poor performance status.