This article is seeking to explain on how the United Nations Security Council has dealt with the problem of countering terrorism. The authors have the objective to provide the process on how the Security Council as the highest body responsible for the maintenance of international peace and Security has taken comprehensive and consistent measures on fighting terrorism that has led to formation of international regime on counter terrorism. Such regime consists of two substantive and structural parts reflected in Security Council resolutions and decisions especially in 1373 resolution. Challenge of a consensual definition of terrorism, requirements for states for cooperation with each other for suppression of terrorism particularly financing of terrorism, prohibition of providing direct or indirect support to terrorism, obligation to implement Security Council sanctions against terrorists enlisted by the UN, and criminalization and prosecution of terrorism in internal legislation by states are main substantive elements of this regime. On the other hand, Counter Terrorism Committee and its Counter Terrorism Directorate as well as procedures under Financial Action Task Force and other international institutions like INTERPOL and ICAO which report to the Council are structural parts of this regime. This article endeavors to provide better knowledge on international regime of counter terrorism and its various aspects functioning in international relations.