Approximately 3 million veterans, slightly more than one-third of all veterans enrolled in the Department of Veterans Affairs (VA) health care system, live in rural areas. This pattern is likely to continue, as a comparable proportion of Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) veterans are from rural areas. The Rural Veterans Care Act of 2006 was signed into law to improve care for rural veterans. Ensuring that the health care needs of rural veterans are met has become a top priority for VA, resulting in a considerable expansion of community based outpatient clinics (CBOCs), inclusion of rural health/access as a research priority, and creation of the VA Office of Rural Health (ORH) in 2006. Although there have been reports comparing health quality of life (both physical and mental) for rural and urban veterans, it remains unclear whether the observed lower health quality of life in rural veterans is due to disparities in health care, differences in disease prevalence, or other population differences. This systematic review examines the evidence regarding potential disparities between rural and urban areas in health care provision and delivery, and how differences in health care may contribute to disparities in health outcomes. Differences in rural-urban prevalence rates of diseases and other health conditions are beyond the scope of this review. Because veterans who use VA health care have been found to use more non-VA health care overall, we expanded the focus of this review to include comparisons of rural vs. urban health care in non-VA health systems. Our first goal was to determine if a health care disparity exists across the urban-rural spectrum. For a disparity to exist, it would have to be demonstrated that health care outcomes of patients in rural areas differ from those of patients treated in urban areas for similar conditions. Because differences in health care process or delivery do not necessarily lead to disparities, we looked for evidence associating differences with poorer health outcomes. For the purposes of this review we conceptualized rural-urban disparities as differences in health care quality or availability. A second goal of the review was to identify areas for intervention should any disparities be found. In order to develop a meaningful intervention, specific information regarding differences in the structure of health care and the way it is administered (i.e., the process) would be critical. Since differences in health outcomes can occur for reasons other than differences in the health care systems themselves (e.g., accessibility), our third goal was to examine what, if any, nonhealth care factors (e.g., travel distance to a clinic) affected health outcomes. Because veterans who use VA health care actually use more non-VA health care overall,9 we expanded the focus of this review to include comparisons of rural vs. urban health care in non-VA health systems The key questions were: Key Question #1. Do adults with health care needs who live in rural areas have different intermediate (e.g., hemoglobin A1c HbA1c], Blood pressure, etc.) or final health outcomes (i.e., mortality, morbidity, quality of life QOL]) than those living in urban areas? Key Question #2. Is the structure (e.g., types of available providers) or the process (e.g., likelihood of referral) of health care different for adults with health care needs who live in urban vs. rural environments? Key Question #3. If there are differences in the structure or the process of health care in rural vs. urban environments, do those differences contribute to variation in overall or intermediate health outcomes for adults with health care needs? Key Question #4. If there are differences in intermediate or final health outcomes for adult patients with health care needs, what other systems factors moderate those differences (e.g., availability of specialists, type of treatment needed, travel distance)?