Medical ethics, autonomy, and self-regulation form the core of medical professionalism. Therefore, codes and guidelines regarding ethics are key documents that demonstrate the identity of physicians as a professional group in a society. In Korea, foreign declarations such as the Hippocratic Oath and the Geneva Declaration have been translated and introduced, while medical ethics guidelines have been introduced from developed countries. In 1961, 1965, and 1979, the Code of Medical Ethics was created and revised, but only in 1997 did Korean doctors develop their own ethics guidelines and codes reflecting their identity in Korean society. In order for these guidelines and codes to be effective living documents, they should be regularly modified to reflect changes in the medical environment and the field of medicine. In response to the urgent need to establish strict norms of medical professionalism in the 21st century due to internal and external problems in Korean society, the Korean Medical Association worked to revise the Ethics Code and Guidelines in 2016. This article reviews the history of how the Korean Code of Ethics and Guidelines has changed and examines the contents of the Code of Ethics and Guidelines as amended in 2016.