Locum tenens is a Latin phrase that means "to hold the place of, to substitute for." In the early 1970s, a federal grant was awarded to the University of Utah for the purpose of providing physician staffing services to rural health clinics in medically under-served areas of the western United States. The program proved so successful that many hospital administrators and physicians began calling for locum tenens physician staffing assistance.

Today thousands of physicians, CRNAs, NPs and PAs contract with locum tenens companies that provide physician staffing services for hospitals, outpatient medical centers, government and military facilities, group practices, community health centers and correctional facilities. The twenty-plus-year industry continues to grow as more and more physicians, CRNAs, NPs and PAs choose this way of practicing medicine.