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An internist, or a doctor of internal medicine, is a physician who specializes in the prevention, diagnosis and treatment of health conditions in adults of all ages. Internists are specially trained on all the internal organs and body systems. They can provide basic preventive care, but they also treat complex medical conditions.
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An internist is a medical doctor who focuses on the primary care of adults (age 18 and over). Internists diagnose and treat injuries and diseases that affect your internal organs. They also focus on disease prevention and health promotion.
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Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy
Internists manage long-term (chronic) illnesses and medical conditions. They commonly see people with:
Internists are frequently called “the doctor’s doctor.” That’s because other doctors ask for their help when trying to solve complicated medical problems. They’re good at:
Other names for internists include:
Internists aren’t the same thing as interns. Interns are doctors in their first year of residency.
Internists have a wide range of duties. As your doctor, they may:
Their tasks may vary, but most internists:
You may see doctors of internal medicine working in a variety of settings. This includes outpatient offices and clinics, hospitals and private practices.
Many internists provide care in outpatient offices and clinics that are connected to a hospital system. You’ll go to them in their office for routine and complex care. They may also provide care for you in the hospital if you need hospitalization.
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Internists who work in hospitals are called hospitalists. They work with other healthcare providers to provide the best possible medical care, like other doctors, nurses and physician assistants.
Internists who work in private practices have their own patient base. They manage their own schedule and provide routine primary care. They can also help you manage complex health conditions.
To become an internist, you need to get a bachelor’s degree. Then, you go on to a four-year medical school. After medical school, you need to complete a residency in internal medicine. This is also called categorical training. This residency usually takes three years.
After residency, you may choose to become board-certified in internal medicine. Or you may go on to practice general internal medicine. About 50% of internal medicine residents choose this path. They serve as primary care doctors or hospitalists.
Other residents pursue extra training in a special area that interests them. This extra training is called a fellowship. A fellowship usually takes two to three years. Specialties that you may choose include areas that are exclusively certified by the American Board of Internal Medicine. These include:
After you complete this training, you may choose to get board-certified in another area. The following are specialties that are certified by the American Board of Internal Medicine, along with another specialty board:
If you’re looking for a primary care provider, an internist may be a good option. An internist, or a doctor of internal medicine, is a healthcare provider who can help you prevent and manage a wide range of health issues.
An internist can screen you for common diseases and prescribe medication. They can refer you to specialists when needed. They can also guide you if you’re trying to lead a healthier lifestyle. It’s important to have a good relationship with your internist. So, make sure you find one who fits your needs.
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Last reviewed on 10/13/2025.
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