This retrospective analysis of 460 malpractice claims describes the types of events that contributed to unsafe care. The surgeon-reviewers identify several problems in the categories of diagnosis and treatment that occurred more frequently in the preoperative and postoperative periods than intraoperatively. The reviewers also rate the surgical care quality and whether the complications leading to the suit were preventable. The American College of Surgeons intends to use these findings to promote educational efforts and patient safety awareness around the identified areas for improvement. Anesthesia and obstetrics and gynecology have also used closed claim reviews to identify opportunities for error prevention.