Clinical indicators are increasingly developed and promoted by professional organizations, governmental agencies, and quality initiatives as measures of quality and performance. To clarify the number, characteristics, and validity of indicators available for anesthesia care, the authors performed a systematic review. They identified 108 anesthetic clinical indicators, of which 53 related also to surgical or postoperative ward care. Most were process (42%) or outcome (57%) measures assessing the safety and effectiveness of patient care. To identify possible quality issues, most clinical indicators were used as part of interhospital comparison or professional peer-review processes. For 60% of the clinical indicators identified, validity relied on expert opinion. The level of scientific evidence on which prescriptive indicators ("how things should be done") were based was high (1a-1b) for 38% and low (4-5) for 62% of indicators. Additional efforts should be placed into the development and validation of anesthesia-specific quality indicators.