The practice of national courts on the application of the provisions of article 4 of Protocol № 7 to the Convention for the protection of human rights and fundamental freedoms indicate a lack of elaboration of the methodology for the application of the principle of non bis in idem. This is due to a certain lack of theoretical reflection on issues of ensuring the right not to be prosecuted or re-punished reflected in the decisions of the European court of human rights. Therefore, this article examines issues of determining the scope of article 4 of Protocol № 7, including through the application of the Engel criteria. The article also notes the importance of assessing the relevant circumstances of the case by means of the developed algorithm ECHR: a) whether the first production of a criminal nature; b) whether the offences for which the applicant pursued, the same (idem); с) there was a duplication of proceedings (bis). In addition, the publication examines the legal nature of such categories as «final solution», «criminal prosecution», «punishment», «the same offence».