Jus cogens raises a vital interest of judicature and doctrine of international public law. We may find different views and opinions on the problem of the existence of peremptory norms, as well as their content. On the basis of the analysisof the practice of international judicial bodies, the article constitutes an attempt to define the prerequisites of a jus cogens norm as well as it aims at determination of a current catalogue of peremptory norms. Moreover, this catalogue evolves over time and in future it might be expected that new jus cogens norms will be recognized by the international community.