20 Types of Doctors and What They Do

The Most Common Specialties in the U.S.

There are around one million physicians practicing in the United States. While some physicians specialize in diagnosing and treating the whole body, other types of doctors focus on a particular part or system, such as the skin or the eyes.

Common types of doctors you might see include:

  • Family medicine
  • Internal Medicine
  • Pediatrician
  • Obstetricians/gynecologist (OBGYNs)
  • Cardiologist
  • Oncologist
  • Gastroenterologist
  • Pulmonologist
  • Infectious disease
  • Nephrologist
  • Endocrinologist
  • Ophthalmologist
  • Otolaryngologist
  • Dermatologist
  • Psychiatrist
  • Neurologist
  • Radiologist
  • Anesthesiologist
  • Surgeon
  • Physician executive

This article explains more about each of these 20 common physician specialties. It's meant for those who want to know what different doctors do, as well as those considering the choice of specialties in a career as a physician.

5 common physician specialties

Verywell / Ellen Lindner

Family Physician

Family practice physicians are primary care providers who see patients of all ages and provide basic care for a variety of common ailments. They are usually the first to recognize major health problems, order diagnostic tests, and refer patients to specialists when needed.

After attending medical school, family medicine physicians attend a family medicine residency program for three to five years. During this time, they will receive hands-on training in pediatric care, emergency medicine, and other areas of general medicine.

What Is a Residency?

Residency is a post-graduate period in which a doctor practices medicine under the supervision of more senior physicians for three to seven years, depending on the specialty.

Internal Medicine Physician

General internists provide primary care to adult patients.

Internists usually have more hospital-based training than family practitioners. They may have an office-based practice or work as a hospitalist primarily seeing patients in the hospital.

These physicians attend medical school followed by an internal medicine residency.

Internists may then choose to pursue a fellowship to subspecialize in a variety of other areas, like endocrinology (hormone-related conditions) or cardiology (heart-related issues).

What Is a Fellow?

A fellow is a physician who attends fellowship training. A fellowship is somewhat like a paid internship during which fellows shadow experts and leaders in their field. The training may involve clinical and surgical practice as well as research.


Pediatricians take care of patients from infancy through age 18 or, in some cases, age 21.

Pediatricians provide primary health care to children, including vaccinations, general health checkups, school physicals, and treatment of issues like coughs, colds, and stomach flu.

If a patient has a more serious illness, their pediatrician may refer them to a pediatric subspecialist (e.g., a pediatric orthopedist is a doctor who specializes in treating young patients with bone and muscle concerns).

After they graduate from medical school, pediatricians spend at least three years in a residency program that is focused on pediatric medicine. If they choose to study a pediatric subspecialty, they will then attend a fellowship for that subspecialty.

Obstetrician/Gynecologist (OB/GYN)

A gynecologist is a doctor who specializes in female reproductive health, including menopause and hormone problems. An obstetrician provides care for people who are pregnant. Obstetricians also are trained to deliver babies.

Often, these specialities are combined, in which case the physician is referred to as an OB/GYN.

At minimum, OB/GYNs must attend medical school followed by a residency program. Once their residency is complete, some continue their training with a fellowship for a subspecialty. Gynecological oncology—a field that deals with cancer of the female reproductive organs—is just one example.


Cardiologists focus on treatment of the heart and its blood vessels. This can include the management of heart failure, cardiovascular disease, and post-operative care.

Training to become a cardiologist is fairly extensive. After completing three years of internal medicine residency, aspiring cardiologists need to attend several more years of fellowship training.


Oncology is a subspecialty of internal medicine that has three main areas: medical, surgical, or radiation oncology.

Oncologists take care of patients who have cancer by treating the disease itself, as well as the symptoms it causes.

Often, oncologists take part in clinical trials using new and experimental treatments for cancers that are otherwise incurable.

Oncologists attend medical school followed by an oncology residency. There are also fellowships for subspecialties of oncology, like pediatric oncology (children's cancer) and radiation oncology (radiation treatment for cancer).


Gastroenterologists treat the functions and diseases of the digestive system.This field attracts physicians who enjoy doing procedures, but who also like seeing patients in an outpatient setting.

Gastroenterology is another subspecialty of internal medicine. At minimum, gastroenterologists attend medical school followed by an internal medicine residency. From there, they need to attend fellowship training for gastroenterology.


Pulmonologists treat the cardio-pulmonary system, which consists of the heart, lungs, and organs involved in the respiratory process.

In addition, pulmonologists may work in office settings to treat patients with breathing disorders, severe allergies, lung problems, and other respiratory diseases. They may also treat patients with pulmonary disease who are in the intensive care unit (ICU).

Aspiring pulmonologists attend medical school followed by an internal medicine residency. They then attend fellowship training for pulmonology.

What Is an Intensivist?

An intensivist is a physician who works in the intensive care unit treating critically ill patients. In addition to medical school and residency, these doctors also do a fellowship in critical care medicine.

Infectious Disease Physician

Infectious disease physicians deal with infections that are hard to diagnose or treat.They also treat serious infections such as the swine flu, bird flu, HIV/AIDS, and other infectious diseases.

After medical school, infectious disease physicians must attend an internal medicine residency followed by fellowship training for infectious diseases.


Nephrologists treat kidney disease and prescribe dialysis for those experiencing kidney failure.

After medical school, these physicians attend an internal medicine residency program. They are then required to attend fellowship training for nephrology.


Endocrinologists treat the endocrine system—the glands that produce and secrete hormones that control and regulate nearly all of the body's functions. People with diabetes or thyroid disease are often treated by an endocrinologist.

Like other internal medicine physicians, endocrinologists attend medical school followed by an internal medicine residency. They are then required to attend fellowship training for endocrinology.

Physician Supply and Demand

A 2020 report from the American Association of Medical Colleges projects a shortfall of up to 55,200 primary care physicians and up to 86,700 specialty physicians by 2033. That's due to both an aging population and physicians retiring earlier. It's also based on current levels of access. If more people can access health care in coming years, up to 145,500 additional physicians may be needed.


Ophthalmologists are medical doctors who treat diseases or disorders of the eyes, such as cataracts and glaucoma.

Vision correction that cannot be handled by an optometrist may be treated by an ophthalmologist. When necessary, ophthalmologists will also perform eye surgery.

Ophthalmologists attend medical school followed by a residency for ophthalmology. They are not required to take a fellowship, although many choose to attend fellowship training for specific eye diseases or surgical procedures.


Otolaryngologists are more commonly referred to as ENTs, or ear/nose/throat doctors.

Otolaryngology is a field that entails a combination of surgical skills and office-based medicine and treatment. They are required to attend medical school in addition to residency for otolaryngology.

ENTs handle a lot of issues, including sinus problems, allergies, head and neck cancers, and more. Because of this, many ENTs attend fellowships for a subspecialty of otolaryngology, such as rhinology, which focuses on issues related to the nose and sinuses.


Dermatologists diagnose and treat conditions that affect the hair, skin, and nails. This may include treating rashes or acne, diagnosing melanoma (skin cancer), and much more.

In addition to this, dermatoligists also perform many aesthetic procedures that are paid for out of pocket rather than by insurance. Such procedures include Botox injections, laser skin treatments, and more.

After medical school, dermatologists must attend dermatology residency. Fellowships are not required, but some dermatologists may attend them if they choose to subspecialize in a particular aspect of dermatology.

Dermatology is a very competitive field for physicians. One reason for this is that dermatologists are very well compensated.Typically, only the top medical students are accepted into dermatology residency programs.


A psychiatrist specializes in mental health. They treat emotional and behavioral problems through a combination of psychotherapy, psychoanalysis, medication, and hospitalization.Their work may be office-based, hospital-based, or a combination of the two.

After medical school and residency for psychiatry, some psychiatrists attend fellowships for a subspecialty. There are a number of different specialty areas within psychiatry, including child and adolescent psychiatry, addiction medicine, or eating disorders.

Psychotherapy vs. Psychoanalysis

Psychotherapists use talk therapy to help people resolve emotional or mental health challenges. Psychoanalysts help people bring unconscious conflicts or repressed memories to the surface so that they can consciously work through them.


Neurologists are doctors who take care of patients with medical conditions that affect the brain, spine, or nerves.

They see patients who have complex medical disorders such as Parkinson's disease, multiple sclerosis, and neuropathy. Neurologists also take care of patients who have common problems such as migraine headaches and dizziness.

Like other physicians, neurologists must attend medical school then a residency for neurology. From there, they may pursue fellowship training for a subspecialty, such as pediatric neurology or vascular neurology (related to blood vessels in the brain).


A radiologist is a physician who is trained in viewing and interpreting diagnostic tests.

Often, the treating physician must interpret test results as well. The radiologist's analysis can offer additional information or advice for further testing.

Before a radiologist is licensed, they must attend medical school and a residency for radiology. From there, they may choose to attend fellowship training for a subspecialty of radiology that is focused on a specific aspect of radiology or area of the body.


Anesthesiologists are trained to manage patient pain and vital signs during surgery.They also often manage medical emergencies in the hospital, such as cardiac arrest and sudden breathing problems.

Aspiring anesthesiologists must attend medical school followed by a residency program for anesthesiology. There are numerous subspecialties of anesthesiology they may attend fellowships for, including anesthesia for patients with chronic pain or for patients in the ICU.


Surgeons spend time planning a surgical procedure, performing surgery in the operating room, and then following up afterwards to identify any complications and confirm that the procedure was a success.

Surgeons can be trained in general surgery or in more specialized areas of surgery, such as hand surgery, pediatric surgery, or vascular surgery (related to blood flow problems).

The training to become a surgeon is typically several years longer than training for a primary care doctor. Following medical school, general surgeons must attend a residency program for three to five years. Once they are board certified, they will attend a fellowship or internship in a surgical department.

Physician Executive

Some physicians do not practice medicine. Instead, they take leading roles in health care policy, pharmaceutical research, or health insurance companies.

Non-clinical doctors generally are required to have completed medical school and residency. They must also maintain a medical license.


Being familiar with the different types of physician specialties helps you know who to call when you need medical care. It also helps those planning a career in medicine, as they think through what they'd like to do on a day-by-day basis.

The Association of American Medical Colleges maintains a database of more than 135 specialties and subspecialties that you can explore. It will help you to understand more about the type of provider you need—or want to become.

23 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  9. American College of Gastroenterology. What is a gastroenterologist?

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  11. Infectious Diseases Society of America. What is an ID specialist.

  12. American Society of Nephrology. About ASN.

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By Andrea Clement Santiago
Andrea Clement Santiago is a medical staffing expert and communications executive. She's a writer with a background in healthcare recruiting.