Physician credentialing is when a medical expert's skills and knowledge are verified and documented. The expert's licensing, education, decision-making skills, and training are all checked over during the process. Many different types of groups and organizations implement the process. It is used in order to verify that a medical professional is qualified to perform the work that they are given. This prevents unqualified individuals from posing as professional physicians and causing harm or injury to others due to inferior schooling or judgment skills. The criteria are verified through third-party peer review. The review is supervised by other medical experts. The process must be officially approved in a lawful manner, and the strategies of physician credentialing must be made transparent.

The criteria that are being measured must be directly linked to the way in which the patient is treated and cared for from a medical perspective, since this is how scoring is determined. The exact nature of the criteria will depend on the type of work that the physician specializes in. In general, doctors are split into two different categories. These are Doctor of Medicine and Doctor of Osteopathic Medicine. In addition to this, there are different fields within each category, such as surgery, general medicine and psychiatry.

Organizations that take note of physician credentialing most often are health insurance companies and medical facilities. Many insurers will refuse to compensate a doctor or their employer unless the doctor has recently undergone the medical credentialing process. The doctor must go through this type of process in order to be able to work with patients who have Medicare as well. A doctor cannot bill Medicare if they have not been approved beforehand. In large part, the process exists not only to assure safety for all parties involved, but to protect outside entities from the threat of associated lawsuits.

Other organizations that may be interested in the process include government health agencies, industry professional associations, philanthropists, and private corporations with their own medical staff. Not only are skills and training tested, a background check is often performed as well. State medical licenses, board certifications, colleges, places of internship, and residency are all contacted and spoken with. References are contacted, claims histories are followed up on, the situation with the Department of Health and Human services is verified, and status with memberships is investigated.

Credentialing almost always starts before a healthcare professional begins to work in their field. It rarely ends after employment begins, and tends to continue periodically for the rest of the doctor's professional life.