Anesthesiologists are medical doctors who specialize in anesthesiology, which is the medical science of relieving pain and managing the body's vital functions, such as breathing, heartbeat, circulation, temperature, and consciousness.

An anesthesiologist may administer medicine that numbs the area of the body where a procedure is being performed (regional anesthesia) or make sure a person is unconscious and pain-free during a procedure (general anesthesia). An anesthesiologist may also supervise an anesthesia assistant. Anesthesiologists can further specialize in areas such as critical care medicine, pain management, pediatric anesthesia, cardiac anesthesia, or obstetric anesthesia.

Anesthesiologists are certified by the Royal College of Physicians and Surgeons of Canada.