This paper reviews the definition of international humanitarian law, as well as the application of international humanitarian law by the International Criminal Court. The powers and activities of the International Criminal Court are examined. The scope of possible application of the principles and provisions of international humanitarian law by the International Criminal Court, as well as the modalities of such application, is revealed. The article analyses changes in Armenian legislation after the ratification of the Rome Statute and focuses on the fact that after the ratification of the Rome Statute, which is a significant step forward for the security of Armenia, Armenia (Centre for Truth and Justice) requested the International Criminal Court Prosecutor to initiate a preliminary examination of the ongoing genocide committed by Azerbaijan’s Armed Forces against the ethnic Armenians within the territory of Armenia. Besides this, the analysis of the procedural position of the International Criminal Court Prosecutor in the system of international justice is carried out. The main tasks and fundamental role of the Prosecutor's office in the investigation or prosecution of international crimes are investigated. Keywords: International Criminal Court; International Humanitarian Law; Rome Statute; ratification; preliminary examination.