The refugee crisis has affected the whole world. The reasons for migration are different from the state and the place, the most common reasons being escape from the war, search for a better life, leaving the dysfunctional states, and escaping from various forms of extremism and terrorism. The main migration flows are directed towards highly developed countries and areas where the European Union is the most desirable but also the easiest achievable destination in the Republic of Croatia. The enormous uncontrolled influx of Islamic migrants into the European Union, irrespective of the measures taken and legal restrictions, has made the concession that this issue, as well as the issue of border control and security, focuses on the protection of national interests of certain countries. It seems that the refugee crisis has never been as current as today due to the large influx of migrants and refugees from the Middle East whose ultimate destination is the European Union. But what is evident is that the states and institutions of the European Union have recently recognized or underestimated the Islamic migration problem as a phenomenon that poses a major security risk to the violence and terrorism of the country in which they are located. Terrorism and terrorist attacks have been present in the world since ancient times, and today it is widely spread all over the world and represents the strongest force in international relations. The reason for terrorism is increasingly to achieve human rights and freedoms, the struggle for democracy, and the largest number of terrorist attacks are recorded by Islamist migrants. More than a million Islamist migrants entered the EU's space in 2015, this figure is growing every day. This paper deals with the arrival of migrants, especially from the Middle East in the European Union, focusing on the Croatian area. Though almost all states use terrorism and persistent attacks to endanger the international and international security and community, the facts say that Croatia is one of the safest states in the European Union. A great reason for this is the fact that migrants from the Middle East, Croatia as a country are used only as a transition country, but not retention.