In March 1982, the American Ambulance Association (AAA) sponsored a Needs Assessment Workshop in Kansas City, Missouri, to analyze the status of the EMS industry. The participants compiled a list of the twenty most pressing issues facing emergency medical services, the first of which was the need for high quality industry standards. In May 1984, the AAA Board of Directors authorized the formation of its Ad Hoc Committee on Accreditation and Standards. The standards that grew out of this committee's work were consensus-based--with input from professionals across the EMS industry. The development of the process by which an agency could become certified to these standards followed.

In 1990, an independent Commission on Accreditation of Ambulance Services (CAAS) was incorporated, bringing together a board of representatives from the American Ambulance Association, the Emergency Nurses Association, the International Association of Fire Chiefs, the National Association of Emergency Medical Technicians, the National Association of EMS Physicians, and the National Association of State EMS Directors. In 1993, the first agencies were accredited by the Commission.

In 2007, there are more than 100 CAAS-accredited agencies in 34 U.S. states and Nova Scotia, and City of Calagary, Alberta Canada, with more than 200 agencies working on new applications.  See the CAAS Accredited Agencies Map.