The National Ambulatory Medical Care Survey (NAMCS) is designed to meet the need for objective, reliable information about the provision and use of ambulatory medical care services in the United States. NAMCS began in 1973 as a national probability sample survey of visits to nonfederally employed office-based physicians. NCHS conducted the survey annually through 1981, again in 1985, and annually through 2021 (collection of visit data from physicians was stopped during 2020–2021 due to the burden placed on respondents by the COVID-19 pandemic). In 2006, a separate sample of Community Health Centers (CHCs) was added to the survey; the CHC component samples visits to both physicians and advanced practice providers (nurse practitioners, PAs [physician assistants and physician associates], and certified nurse midwives). Starting in 2012, in addition to the traditional NAMCS file, a separate data file for CHCs including physicians and advanced practice providers has been released.

In 2021, the former CHC sample of NAMCS was redesigned and launched as the NAMCS Health Center (HC) Component, collecting visit data from HCs using electronic health records, or EHR, systems of the participating health centers. The NAMCS Health Center Component contains critical data about health centers and the care they provide.