Assessing quality of care at the end of life involves measurements in several domains-use of evidence-based guidelines, patient and family satisfaction, quality of life, and incidence of adverse events, among others. There are several different data sources from which to calculate quality measures. Each data source has a balance of strengths and weaknesses, and not all data sources are available in all possible settings of care. This paper describes how various data sources can be used to obtain the key data elements required for quality of care measures, as well as the challenges to linking data elements across sites and levels of care. There are some important quality domains (e.g., interpersonal and spiritual aspects of care) that are very difficult to assess using readily available data; primary data collection through interview and survey methods will be required to assess quality in these areas.