The Physician Assistant profession evolved in the United States during the mid-1960s, in response to a shortage and uneven geographical distribution of doctors working in primary care. The first trainees were highly skilled military medics who, following Vietnam War service, had no equivalent medical role in civilian life. PAs continue to be a safe and effective part of the U.S. health system with over 63,000 practicing PAs and 139 accredited programs.

Mid-level clinicians have been employed by the Canadian Forces (CF) for over 50 years and in 1984 the first class of “Physician Assistants” graduated from the Canadian Forces Medical Services School at Borden Ontario. They are generally acknowledged as the first formally trained PAs in Canada.
In 1997 Warrant Officer Thomas Ashman, stationed at Canadian Forces Station Alert as a PA, conceived the idea of a National Academy of Canadian PAs. In October 1999 the Canadian Academy of Physician Assistants (now the Canadian Association of Physician Assistants- CAPA) was formed; Thomas Ashman was elected founding president. CAPA’s goal was to be a national professional organization that advocated for Physician Assistants and represented its membership across Canada (By PAs for PAs).
In 1999, the Canadian Forces funded the development of CAPA with the intent that it would become self-sufficient and expand to include a civilian component. In September 2001 CAPA, with assistance from the Canadian Forces Medical Services School, developed the Occupational Competency Profile for the Civilian PA in Canada; this OCP was adopted by the Canadian Forces. In September 2002, the Canadian Forces inaugurated a redesigned PA program to align with requirements for accreditation by the Canadian Medical Association.
In June 2003, the Canadian Medical Association recognized the PA as a health professional. This paved the way for an accreditation process to begin; in June 2004 CMA/ARC-PA surveyed the Canadian Forces PA program for accreditation as a certificate-awarding program.
In 2003, Manitoba enacted legislation allowing PAs to function as Clinical Assistants; the province currently has numerous PAs practicing in medical and surgical specialties. In 2007, the Ministry of Health and Long-Term Care for Ontario announced the inclusion of PAs in Ontario’s provincial health care system.