Checklists have been responsible for some of the most remarkable successes of the patient safety era, particularly in improving safety for patients undergoing surgery. However, recent studies have raised concern that surgical checklists may not realize their promise in real-world settings. This systematic review, performed originally for the AHRQ Making Healthcare Safer II report, found broad evidence that surgical safety checklists (including the SURPASS checklist and the World Health Organization checklist) are effective at preventing intraoperative and postoperative complications. The review also identifies factors associated with successful implementation of the checklists, information that is essential in order to translate research findings into daily clinical practice.