ACP Facts


The American College of Physicians (ACP) is a national organization of internal medicine physicians – specialists who apply scientific knowledge and clinical expertise to the diagnosis, treatment, and compassionate care of adults across the spectrum from health to complex illness. Internal medicine specialists are the largest group of practicing physicians in the U.S. and deliver much of the primary care that is provided. They are especially well-trained in the diagnosis of puzzling medical problems, in the ongoing care of complicated illnesses, and in caring for patients with more than one disease. Internal medicine physicians not only treat disease but also coordinate health care and play a critical role in preventing disease and promoting health and well-being.

Internal Medicine Physicians and Subspecialists

An M.D. or D.O. who completes a three-year internal medicine residency program is an internal medicine physician or internal medicine subspecialist. The general internal medicine physician is an expert in the general care of the adult but also may have special areas of expertise. A subspecialty internal medicine physician is an internal medicine physician with one to three years of additional training in a particular organ (nephrology/kidney), system (endocrinology/glands), or age group (geriatrics). Some internal medicine physicians practice a combination of both general and subspecialty medicine.

Mission and History

The ACP mission is to enhance the quality and effectiveness of health care by fostering excellence and professionalism in the practice of medicine. ACP was founded in 1915 to promote the science and practice of medicine. In 1998, ACP merged with the American Society of Internal Medicine (ASIM), which was established in 1956 to study economic aspects of medicine.


With 161,000 members, ACP is the largest medical specialty organization and second-largest physician group in the United States. ACP provides information and advocacy for its members as they practice internal medicine and related subspecialties such as cardiology and gastroenterology. ACP members are also involved in medical education, research, and administration.

Levels of ACP membership are Medical Student, Associate, Member, Fellow (FACP), Honorary Fellow, and those elected to receive Mastership (MACP). Fellowship and Mastership recognize achievements and outstanding contributions in internal medicine.

ACP Publications

Annals of Internal Medicine is one of the top medical journals in the world. ACP JournalWise summarizes the most important medical articles from more than 120 journals. I.M. Matters from ACP is an award-winning semi-monthly newspaper for internal medicine physicians, while ACP Hospitalist is written for those in hospital practice. The ACP Advocate is a bi-weekly e-newsletter that provides ACP members with news about critical public policy and regulatory issues affecting internal medicine and patient care.


The ACP Washington, D.C., office monitors and responds to policy and regulatory issues that affect public health and the practice of medicine. Activities include development of policy statements and communications with legislative and administrative sectors of government, as well as the development of practice-support tools to enhance the efficiency, quality, and delivery of care.

The Center for Ethics and Professionalism seeks to advance physician and public understanding of ethics and professionalism issues in the practice of medicine in order to enhance patient care by promoting the highest ethical standards.

Education and Information Resources

ACP supports the optimal practice of medicine by providing opportunities for continuing medical education. ACP medical education programs include the development of evidence-based clinical practice guidelines.

ACP’s Medical Knowledge Self-Assessment Program (MKSAP) gives internal medicine physicians an opportunity to test their knowledge and compare their results with national averages. In addition, ACP offers postgraduate board review courses, recertification courses, and chapter/regional meetings. For future internal medicine physicians, ACP provides education and career information, produces, and administers an In-Training Examination for residents.


ACP is governed by an elected Board of Regents. The Board is advised by a network of ACP committees and by the ACP Board of Governors, which is composed of elected Governors in chapters and regions of the United States. ACP has international chapters in Bangladesh, Brazil, Canada, Caribbean, Central America, Chile, Colombia, India, Japan, Mexico, Saudi Arabia, and Venezuela.

ACP is a founding member of the Council of Medical Subspecialty Societies, which represents 50 subspecialty societies and internal medicine organizations. ACP also engages in multiple collaborations on a range of topics and is represented by a large delegation to the American Medical Association.

Officer and Staff Spokespersons

2023-24 President Omar T. Atiq, MD, MACP, Little Rock, AR
2023-24 Chair, Board of Regents Eileen D. Barrett, MD, MACP, Albuquerque, NM
President-elect* Stephen D. Sisson, MD, MACP, Baltimore, MD
Chair-elect, Board of Regents* William E. Fox, MD, FACP, Charlottesville, VA
Executive Vice President and CEO Darilyn V. Moyer, MD, MACP, Philadelphia, PA

* to take office as 2024-25 President and Chair, Board of Regents, April 20, 2024.