Audit is a term used to include case reviews, criterion-based clinical audit, enquiries into maternal mortality and perinatal deaths, and near-miss reviews. The audit cycle consists of identifying cases, collecting information, analysing the results, formulating recommendations, implementing change and re-evaluating practice, and this cycle must be repeated regularly. Implicit in the process are standards against which practice is measured. These standards are becoming increasingly explicit and may be based on hospital protocols or regional or national guidelines. When protocols or guidelines are drawn up, this must be on the basis of multidisciplinary discussion and they need to be regularly updated as new evidence emerges. Audit does not need to be expensive, but it does need the support of all staff, including managers and clinicians. Staff must understand that its purpose is not to identify errors and punish mistakes but to improve clinical care.