Colorectal surgery is a field in medicine dealing with disorders of the rectum, anus, and colon. The field is also known as proctology, but this term is now used infrequently within medicine and is most often employed to identify practices relating to the anus and rectum in particular. The word proctology is derived from the Greek words πρωκτός proktos, meaning "anus" or "hindparts", and -λογία -logia, meaning "science" or "study".

Physicians specializing in this field of medicine are called colorectal surgeons or proctologists. In the United States, to become colorectal surgeons, surgical doctors have to complete a general surgery residency as well as a colorectal surgery fellowship, upon which they are eligible to be certified in their field of expertise by the American Board of Colon and Rectal Surgery or the American Osteopathic Board of Proctology. In other countries, certification to practice proctology is given to surgeons at the end of a 2–3 year subspecialty residency by the country's board of surgery.