The Indian Health Service (IHS), located within the Department of Health and Human Services, is responsible for arranging health care services for Native Americans (American Indians and Alaska Natives). IHS services include primary care (medical, dental, and vision); ancillary services, such as laboratory and pharmacy; and specialty care, including services provided by physician specialists. IHS provides some services through direct care at hospitals, health centers, and health stations, which may be federally or tribally operated. When services are not available—that is, both offered and accessible—on site, IHS offers them, as funds permit, through contract care furnished by outside providers. Concerns persist that some Native Americans are experiencing gaps in necessary health care. GAO was asked to examine the availability of (1) primary care services and (2) ancillary and specialty services for Native Americans. Additionally, GAO examined the underlying factors associated with variations in the availability of services and strategies used by facilities to increase service availability. GAO conducted site visits to 13 facilities and interviewed IHS officials from all 12 IHS areas, which cover all or part of 35 states. GAO received written comments from IHS. IHS substantially agreed with the findings and conclusions of this report.https://www.gao.gov/products/GAO-05-789