The purpose of this thesis is to identify and explain the causes of instability in Muslim-Croat relations in the period between 1990-1997. These two nations are supposed to be the main pillars of the new Bosnian state born in Dayton, Ohio on November 21, 1995. So far, the Serbs have eschewed all efforts of the International Community in the direction of the stronger integration of a Bosnian state, and there are no signs of possible improvement in the future. If the project of a Muslim-Croat Federation fails, the whole state is at stake. Muslim leadership, along with many historians and political analysts hold the Croats responsible for the deterioration of Muslim-Croat relations, but a number of important developments do not fit this assumption. The author will argue that although the Muslims and the Croats did not create their alliance in the Bosnian war in good faith, the main cause of deterioration of Muslim-Croat relations is the wavering policy of the international community toward the Yugoslav crisis.