In the last years the Iranian Islamic Republic has faced international concerns and sanctions for its controversial nuclear program. A potential nuclear weapon would represent a serious threat for the troubled region of the Middle East and for the international community. However, less is known about the predicament of the Iranian regime and its internal rationales for the implementation of the nuclear agenda. The author, therefore, evaluates four domestic motivations and functions of the nuclear program in the Iranian Islamic Republic. They have emerged as a result of two peculiarities: first, the Iranian uniqueness in being the only Shi’a country, the only theocratic regime in the world and the successors of the great Persian civilization. Second, the Iranian fear of threats such as the invasions of Islam, the Mongols and the Western powers in 19th and 20th century. The author ultimately discusses the risks of a potential nuclear device for the security of Israel by evidencing the negative attitude that the Iranian regime has demonstrated toward Israel in the last decades.