Improving quality of life (QOL) in oncology patients is an important therapeutic goal, and most treatment decisions are heavily influenced by their effect on QOL. Although measuring QOL has been a significant challenge because of a lack of consensus on the definition of QOL, research in this field has advanced rapidly. Numerous instruments now exist for measuring QOL and symptom burden, ranging from general health status measures to considerably more focused symptom measures. QOL measures have been routinely incorporated in clinical trials, and their use in clinical settings is strongly encouraged because their value in cancer patient management is now established. These measures also have a potential impact in the managed care environment because they provide information on patient satisfaction and quality of care provided. This article clarifies the definition of QOL, provides a brief overview of several useful measurement instruments, and addresses some common concerns encountered in measuring QOL in cancer patients. In addition, potential uses of such measures are explored and their value in various settings, including managed care, is highlighted.