Citizenship is an institute that is slowly created through history. The origins of citizenship appeared 700 years before Christ, while the modern citizenship only since the late 18th and early 19th centuries. Citizenship is inextricably linked with the concept of the nation. The paper mentions a stranger, and that can be determined, the difference stranger and refugees. A natural person can acquire the nationality of two or more states. People with two nationalities are called bipatridima, a person with multiple nationalities are called polipatridima. Stateless and stateless persons do not enjoy the protection of any sovereign state. Therefore, the international community is trying to various international agreements to ensure the minimum rights that are associated with citizenship. Citizenship preference is given to the principle of acquiring citizenship by origin, and based on the principle of full equal status of man and woman, father and mother, complete the tie of marriage and illegitimate children. According to the Croatian citizenship possible are four ways to acquire Croatian nationality: origin, birth on the Croatian territory, naturalization, according to international treaties. In Croatia, the Croatian Citizenship Act provides for three modes of termination of Croatian citizenship: release, waiver, according to international treaties.