Surgical procedures are commonly categorized by urgency, type of procedure, body system involved, the degree of invasiveness, and special instrumentation.

• Based on timing: Elective surgery is done to correct a non-life-threatening condition, and is carried out at the person's request, subject to the surgeon's and the surgical facility's availability. A semi-elective surgery is one that must be done to avoid permanent disability or death, but can be postponed for a short time. Emergency surgery is surgery which must be done promptly to save life, limb, or functional capacity.
• Based on purpose: Exploratory surgery is performed to aid or confirm a diagnosis. Therapeutic surgery treats a previously diagnosed condition. Cosmetic surgery is done to subjectively improve the appearance of an otherwise normal structure.
• By type of procedure: Amputation involves cutting off a body part, usually a limb or digit; castration is also an example. Resection is the removal of all of an internal organ or body part, or a key part (lung lobe; liver quadrant) of such an organ or body part that has its own name or code designation. Excision is the cutting out or removal of only part of an organ, tissue, or other body part from the person. Replantation involves reattaching a severed body part. Reconstructive surgery involves reconstruction of an injured, mutilated, or deformed part of the body. Transplant surgery is the replacement of an organ or body part by insertion of another from different human (or animal) into the person undergoing surgery. Removing an organ or body part from a live human or animal for use in transplant is also a type of surgery.
• By body part: When surgery is performed on one organ system or structure, it may be classed by the organ, organ system or tissue involved. Examples include cardiac surgery (performed on the heart), gastrointestinal surgery (performed within the digestive tract and its accessory organs), and orthopedic surgery (performed on bones or muscles).
• By degree of invasiveness of surgical procedures: Minimally-invasive surgery involves smaller outer incision(s) to insert miniaturized instruments within a body cavity or structure, as in laparoscopic surgery or angioplasty. By contrast, an open surgical procedure such as a laparotomy requires a large incision to access the area of interest.
• By equipment used: Laser surgery involves use of a laser for cutting tissue instead of a scalpel or similar surgical instruments. Microsurgery involves the use of an operating microscope for the surgeon to see small structures. Robotic surgery makes use of a surgical robot, such as the Da Vinci or the ZEUS robotic surgical systems, to control the instrumentation under the direction of the surgeon