Should doctors disclose any of their patients' confidences? When is disclosure justified? Is disclosure ever mandatory? Should there be an absolute rule of non- disclosure? If not, why not? ‘Confidentiality and privacy’ considers these questions and shows that national and international codes of medical ethics acknowledge the undesirability of an absolute rule. Why confidences should be respected, to whom the information should be confidential, and balancing competing interests are all discussed. The cases where the duty of confidentiality must or may be breached are studied and the confidentiality and privacy of children, incapacitous patients, and the dead are also reviewed.