A fellowship is the period of medical training in the United States and Canada that a physician, dentist, or veterinarian may undertake after completing a specialty training program (residency). During this time (usually more than one year), the trainee is known as a fellow or fellow physician. Fellows are capable of acting as an attending physician or a consultant physician in the specialist field in which they were trained, such as internal medicine or pediatrics. After completing a fellowship in the relevant sub-specialty, the physician is permitted to practice without direct supervision by other physicians in that sub-specialty, such as cardiology or oncology.
In the US, the majority of fellowships are accredited by the Accreditation Council for Graduate Medical Education ("ACGME") or, to a lesser extent, the American Board of Physician Specialties in select states. There are fellowship programs that are not ACGME accredited, yet are well received, given the importance of being a Board-Certified Physician in a primary specialty, where a Fellowship is often more based on demand and research productivity.
In general, ACGME accredited programs require completion of ACGME-accredited, RCPSC-accredited or CFPC- accredited residency program, however, exceptions for an ACGME-International- accredited residency programs and non-ACGME-accredited residency programs are possible. International medical graduates must be ECFMG certified. Some fellowship specialties require participation in special matching programs such as Specialties Matching Service (SMS) or SF Match.
There are a number of programs offering a combined fellowship, training in two or more sub-specialties as part of a single program.