ABSTRACT Actually, conflict between Armenia and Azerbaijan in Nagorno-Karabakh was existed since a long time, but the big conflict was started since 1988 with mass demonstration in Nagorno-Karabakh. In 1994, the conflict was settled by agreement named Bishkek Protocol, but the implementation of Bishkek Protocol was failed to be understood and both parties Armenia and Azerbaijan made delinquencies. Then, OSCE as mediators keeps doing mediation process in order to solve Nagorno-Karabakhs conflict. OSCE keeps doing the mediation process in several years but the meeting from mediation cannot give peace settlement, so that conflict in Nagorno-Karabakh can be called as frozen conflict because peace settlement still cannot be reached even though it has been helped by other parties to solve this problem. Key Words: Mediation, Nagorno-Karabakh, Armenia, Azerbaijan, OSCE Minks Group