Almost two decades since conflict broke out between the Republic of Azerbaijan and Armenia, two northern neighbors of Iran, in Nagorno -Karabakh region. Although military conflict in this region has minimized with the existing ceasefire, and reaching a sustainable agreement is likely to be happened by the two parties. Close regional and international cooperation seems necessary more than ever in order to reduce conflict in NagornoKarabakh region. The main objective of this study is to give a thorough presentation of the regional and international cooperation in order to reduce Nagorno -Karabakh regional issues and hazards.Hereunder is the main question raised by the researcher: "To what extent regional and international cooperation is effective in reducing Nagorno -Karabakh conflict?"The hypothesis of the present study is that the interrelated nature of security in the international system and Caucasus region causes convergence among neighboring countries to reduce conflict in Caucasus and NagornoKarabakh regions. Taking advantage of the analytic -descriptive method and also benefiting from reliable and authentic sources, it can be concluded that the interdependence of threat will lead to the increased mutual costs in this study. This issue will cause formation of convergence in the Caucasus region, so that it will lead to the reduced conflict and tension in Nagorno -Karabakh region.