The present paper discusses the relevance and significance of the Hippocratic Oath to contemporary medical ethical and moral values. It attempts to answer the questions about some controversial issues related to the Oath. The text is divided in two parts. Part I discusses the general attributes and ethical values of the Oath, while Part II presents a detailed analysis of each passage of the Oath with regard to perennial ethical principles and moral values. Part I starts with the contribution of Hippocrates and his School of Cos to medicine. It continues by examining the moral dilemmas concerning physicians and patients in the Classical Times and in the Modern World. It also investigates how the Hippocratic Oath stands nowadays, with regard to the remarkable and often revolutionary advancements in medical practice and the significant evolution in medical ethics. Further, it presents the debate and the criticism about the relevance of the general attributes and ethical values of the Oath to those of modern societies. Finally, it discusses the endurance of the ethical values of the Hippocratic Oath over the centuries until today with respect to the physicians' commitment to the practice of patient-oriented medicine. Part I concludes with the Oath's historic input in the Judgment delivered at the close of the Nuremberg "Doctors' Trial"; this Judgement has become legally binding for the discipline in the Western World and was the basis of the Nuremberg Code. The ethical code of the Oath turned out to be a fundamental part of western law not only on medical ethics but also on patients' rights regarding research.