The authors review epidemiological and survey research relevant to the relationships between religiousness/spirituality and mental health in people at the end of life, with the end of helping psychiatrists, psychologists, and other mental health professionals dealing with older Americans. They give special attention to well-being, religious coping, cognitive dysfunction, anxiety, depression, and suicide, and consider the extent to which hope is a mediator of the purported salutary effects of religiousness. Studies were selected from the comprehensive and systematic review of 20th-century scientific literature concerning religion and health. Authors also review current studies relevant to religion and end-of-life issues. Religious persons reported generally higher levels of well-being. The review also found fairly consistent inverse associations of religiousness with rates of depression and suicide. There was some negative association between religious participation and cognitive dysfunction, but the association with anxiety was inconsistent, with some studies showing a correlation between higher levels of religion and anxiety. Religion's effects on mental health are generally protective in direction but modest in strength.