This new edition of the Code of Medical Ethics is the culmination of an eight-year project to modernize the Code's ethical guidance for relevance, clarity and consistency. It represents the first comprehensive review of the Code in more than half a century. The features of this significantly revised edition will allow physicians to more easily incorporate the Code into their daily practice of medicine. The Code of Medical Ethics was adopted at the first AMA meeting in 1847. Much in medicine has changed in 169 years, but this founding document-the first uniform code of ethics of its kind-is still the basis of an explicit social contract between physicians and their patients. It is regularly cited as the medical profession's authoritative voice in legal opinions and in scholarly journals. It should be in every medical library and practice office.