Background. The article outlines the history of the formation of ideas about virtues and vices in the Antiquity and the transformation of their conceptual component over the following centuries. The research focuses on the analysis of their essence, the foundations of which were laid in Greco-Roman and Christian ethics. At the same time, it is in the Middle Ages that it reaches the peak of its cultural significance. Methods. The study is based on linguistic material that represents these concepts in the works of ancient and medieval writers. All the ideas presented are illustrated by examples from the original texts with translation. Results. The concepts of "virtues" and "vices" as key elements of the moral and ethical tradition of antiquity and the Middle Ages are considered, common and distinctive features in the views on their nature are revealed. Philosophers and theologians, guided by their own vision, distinguished different virtues/vices and named different numbers of them. The existence of many points of view on the nature of virtues and vices stemmed from a strong tradition of dividing moral and ethical categories into two systems: the dichotomous system, in which virtues were opposed to vices, and the triad system, where virtue was considered the middle ground between two extreme manifestations of certain inclinations or character traits. Conclusions. Mentions of virtues and vices can be found already in Homer, Aeschylus, Socrates and Xenophon, Plato gives four basic virtues to the ideal citizen, and Aristotle puts forward the theory of dividing virtues into dianetics and ethics and comprehends vices from the standpoint of morality. The doctrine of the four basic virtues was brought to Rome by Cicero and Seneca. Later on, the Christian tradition borrowed it and adapted it to the needs of the Church, adding the theological virtues, a list of which was formulated by the Apostle Paul and developed by Thomas Aquinas. He, as well as Pierre Abelard, speaks of the differentiation of vices and sins. The list of the Seven Deadly Sins was published in 590 by Pope Gregory the Great. We owe their appearance to the early Byzantine theologian Evagrius of Pontus, who developed the doctrine of the eight evil thoughts, and to John Cassian and Eutropius of Valencia. During the Middle Ages, virtues and vices (sins) became the subject of religious and moral discussions, and the Christian tradition settled on a dichotomous approach to their nature.