A residency is the required training every medical school graduate completes to practice independently in a specialty like internal medicine or surgery. A fellowship is an optional step after residency that narrows your focus to a subspecialty, such as cardiology or oncology. In short, residency trains you to be a specialist, and fellowship turns you into a subspecialist.
How the Two Fit Into a Medical Career
Every physician follows the same early path: four years of medical school, then residency. Residency is not optional. It’s where new doctors learn to diagnose, treat, and manage patients across a broad range of conditions within their chosen field. An internal medicine resident, for example, rotates through hospital wards seeing everything from pneumonia to heart failure to liver disease. By the end, they can practice independently and are eligible for board certification in that specialty.
Fellowship comes after. It’s a deeper dive into one corner of that specialty. Using the same example, an internal medicine graduate who wants to become a cardiologist must complete a cardiology fellowship. Without it, they cannot carry out the procedures or hold the subspecialty title that defines that field. While fellowship is technically optional for many physicians, it’s required if you want to practice in a subspecialty like gastroenterology, pulmonology, or surgical oncology.
Length of Training
Residency programs run three to seven years depending on the specialty. Family medicine and internal medicine are on the shorter end at three years. General surgery takes five years. Neurological surgery can stretch to seven. These timelines are set by the Accreditation Council for Graduate Medical Education (ACGME), and each year builds on the last, progressing from closely supervised work to near-independent practice.
Fellowships are shorter, typically one to three years. A cardiology fellowship runs three years. A sports medicine fellowship might be just one. The length reflects how much additional procedural skill and clinical knowledge the subspecialty demands beyond the foundation residency already provided.
What You Actually Do Day to Day
Residents spend most of their time on direct patient care. They’re in the hospital seeing patients, writing orders, performing procedures under supervision, and gradually taking on more responsibility. The workload is broad by design. A pediatrics resident might manage a child with asthma in the morning and a newborn with jaundice in the afternoon.
Fellows still see patients, but the scope is narrower and the expectations are higher. A fellow in rheumatology, for example, manages only rheumatology patients and is expected to handle complex cases with increasing independence. Fellows also take on more responsibilities outside direct patient care. Research published in the Journal of Physical Therapy Education found that fellowship-trained physicians spend significantly more of their workweek on teaching, mentoring, research, and administrative duties compared to those without post-residency training. Many fellowship programs explicitly require a research project or scholarly output as a condition of completion.
The Application and Matching Process
Both residency and fellowship positions are filled through a matching system run by the National Resident Matching Program (NRMP), but the two processes operate on different timelines and structures.
For residency, medical students apply during their final year of medical school through the Electronic Residency Application Service (ERAS), interview at programs, then submit a ranked list of their preferred programs. The Main Residency Match releases results in March.
Fellowship matching works differently. The NRMP’s Specialties Matching Service covers more than 70 subspecialties, each with its own match cycle. Some fellowship programs open applications in July, others in December, and timelines vary by subspecialty. Not all fellowships even use ERAS. Some require their own applications. You need to register with both the NRMP and ERAS separately if your subspecialty uses both systems. The key eligibility requirement: you must have completed all residency training required for the position before starting.
Board Certification Differences
The American Board of Medical Specialties (ABMS) oversees certification for both levels, but the credentials are distinct. After completing residency, you’re eligible to sit for your specialty board exam. Passing makes you board certified in, say, internal medicine or general surgery.
Subspecialty certification adds another layer. You must already hold your primary specialty board certification, then complete fellowship training and pass a separate subspecialty exam. A physician board certified in internal medicine who finishes a pulmonology fellowship and passes the subspecialty exam becomes board certified in pulmonary medicine. This dual certification signals expertise to hospitals, insurers, and patients alike.
Pay During Training
Both residents and fellows earn a salary, but it’s modest compared to what attending physicians make. Pay is tied to your post-graduate year (PGY) level, meaning it increases incrementally each year of training regardless of whether you’re in residency or fellowship.
At the University of Michigan, one of the larger academic medical centers, the 2025-2026 salary scale illustrates the progression. A first-year resident (PGY-1) earns about $74,600 per year. By PGY-4, that rises to roughly $83,900. A fellow entering at the PGY-5 level would earn around $87,300, and a PGY-7 fellow about $94,400. Each year also includes a lump sum payment of roughly 10% of annual salary. These figures are representative of large academic programs, though exact numbers vary by institution and region.
The financial tradeoff of fellowship is real. Every additional year of training is a year of earning a trainee salary instead of an attending salary, which can be two to five times higher. For subspecialties with significantly higher earning potential, such as interventional cardiology, the long-term return usually justifies it. For others, it’s a decision driven more by clinical interest than finances.
Work Hours and Lifestyle
The ACGME caps clinical and educational work at 80 hours per week, averaged over four weeks, for both residents and fellows. Fellows must have at least one day off per seven (averaged over four weeks), at least 14 hours free after a 24-hour in-house call shift, and cannot be on in-house call more than every third night.
In practice, many fellows find their schedules somewhat more predictable than residency. The frantic pace of intern year, with its constant admissions and overnight shifts, typically gives way to a more focused clinical schedule. That said, fellowship often adds research and teaching obligations on top of clinical hours, so the total time commitment can be comparable. The nature of the work simply shifts.
Choosing Between Stopping or Continuing
Not every physician needs a fellowship. If you want to practice general internal medicine, family medicine, emergency medicine, or general surgery, residency alone qualifies you. You can be board certified, practice independently, and build a full career.
Fellowship makes sense if your career goals require subspecialty expertise. You cannot become a cardiologist, gastroenterologist, or neonatologist without one. It’s also the typical path into academic medicine, where research productivity and subspecialty depth are expected. The decision usually crystallizes during residency, as you discover which clinical problems fascinate you enough to spend another one to three years learning to manage them at the highest level.