The importance of religion and spirituality to the American public has been highlighted by recent opinion polls, media attention and empirical studies. Psychosocial researchers are incorporating these variables into studies of emotional and physical illness. A number of studies have found that, for cancer patients, religious, spiritual and quality of life concerns are paramount. This paper reviews the literature relating religion and spirituality to physical and emotional health and quality of life. Definitions and measurement issues related to religiosity/spirituality and quality of life are discussed. The paper provides a rationale and methodological suggestions for future studies assessing religious and spiritual beliefs of cancer patients in relation to quality of life. The authors conclude that regular inclusion of religiosity and spirituality measures in quality of life studies is needed in order to understand the integration of mind, body and spirit in cancer care.