Anesthesiologists are medical doctors who specialize in anesthesiology, which is the use of pain-blocking techniques or medications (anesthetics) during surgery and other medical procedures.

An anesthesiologist may administer medication that numbs the area of the body where a procedure is being performed (local or regional anesthesia), inject medicine into the spinal canal to numb an area of the body (spinal or epidural anesthesia), or make sure a person is unconscious and pain-free during a procedure (general anesthesia) while also monitoring heart rate, breathing, and blood pressure. An anesthesiologist may also supervise a nurse anesthetist. Anesthesiologists can further specialize in critical care medicine, pain management, pediatrics, or obstetrics.

Anesthesiologists can be board-certified through the Board of Anesthesiology, which is recognized by the American Board of Medical Specialties.