Examining health care disparities is an integral part of improving health care quality. Health care disparities are the differences or gaps in care experienced by one population compared with another population. As the National Healthcare Quality Report (NHQR) shows, Americans too often do not receive care that they need or they receive care that causes harm. The National Healthcare Disparities Report (NHDR) shows that some Americans receive worse care than other Americans. Within the scope of health care delivery, these disparities may be due to differences in access to care, provider biases, poor provider-patient communication, poor health literacy, or other factors. The purpose of the NHDR, as mandated by Congress, is to identify the differences or gaps where some populations receive poor or worse care than others and to track how these gaps are changing over time. Although the emphasis is on disparities related to race and socioeconomic status, the reporting mandate indicates an expectation that the Agency for Healthcare Research and Quality (AHRQ) will examine health care disparities across broadly defined "priority populations." These include ethnic minorities and other groups or categories of individuals experiencing disparate and inadequate health care. The NHDR and NHQR use the same measures, which are categorized across four dimensions of quality: effectiveness, patient safety, timeliness, and patient centeredness. This year's report focuses on the state of health care disparities for a group of "core" measures that represent the most important and scientifically credible measures of health care quality for the Nation, as selected by the Department of Health and Human Services (HHS) Interagency Work Group. By focusing on core measures, the 2009 report provides a more readily understandable summary and explanation of the key results derived from the data. Three key themes emerge in the 2009 NHDR: Disparities are common and uninsurance is an important contributor; Many disparities are not decreasing; Some disparities merit particular attention, especially care for cancer, heart failure, and pneumonia; We also summarize efforts by AHRQ and HHS to accelerate the pace of improvement by: Training providers; Raising awareness; Forming partnerships to identify and test solutions.