Improving end-of-life experience is a major challenge to successful aging. Deaths that are reasonably free of discomfort, in accordance with patients' wishes, and within acceptable professional and ethical standards are high-quality deaths. The authors developed a 31-item measure of the quality of dying and death and applied it in a community sample and a sample of hospice enrollees. Scores on the Quality of Dying and Death Instrument and measures of perceived quality of care were collected from patients' loved ones after death. Higher overall after-death ratings of the quality of care received from all providers and from physicians were associated with higher-quality dying and death. How well patients' symptoms were controlled in the community study and how well wishes were followed and treatments were explained in the hospice study were associated with higher-quality dying. Major challenges to end-of-life research include recruiting representative population samples, given widespread reluctance of patients and loved ones to participate in research at the end of life; important variation in evaluations among different reporters after death; reluctance of loved ones to assign negative evaluations to dying experiences after death; and the highly individual and dynamic nature of dying experiences. Overcoming these challenges is of great importance in the search for the social, organizational, and individual determinants of high-quality dying in the U.S. cultural and health care context.