The article touches approach of the modern Islamic legal thought to the Islamic state and caliphate. The author explains the fundamental principles if Islamic concept of the power (caliphate) and points out that this concept was gradually deviating from real political practice. The caliphate itself remained as a political institution till the collapse of the Ottoman Empire after the World War I. After emergence of Islamic State of Iraq and Levant (ISIL) the caliphate converted to concrete political project. In June 2014 ISIL which changed its name to become “Islamic State” (IS) declared creation of caliphate. In practice the Shariat implementation in IS comes to mass killings, forcing nonmuslims to adopt Islam, interference into internal life of Muslim states and terror attacks. The modern Islamic legal thought criticizes IS severely stressing on its violence of religious postulates and Shariat provisions.