In a study of peer reviewer agreement for major anesthetic mishaps, 42 anesthesiologists performed a standardized peer review of 48 reports of anesthetic mishaps obtained from a national data base. The peer review group exhibited agreement (P less than 0.0001) for judgments on the appropriateness of clinical care, the presence or absence of human error, and the role of better monitoring in prevention of the mishap. Personal attributes of the reviewers (eg, type of practice, length of time in practice, and previous experience with mishap review) did not appear to influence agreement. The study findings suggest a highly favorable environment for the development of broadly recognized standards of care in anesthesiology.