The article describes the background, conditions of establishment and the present status of the Islamic State radical organization. The author devotes considerable attention to the takeover of Mosul by the Islamists in June 2014, which is the second most populous city in Iraq. It let them declare the establishment of so called Caliphate in north and west districts of Iraq and North-East Syria. The analysis is given to illegal activities of Islamists` external sponsors: Turkey, Saudi Arabia and Qatar, which gave rise to Islamic State extensively. Formerly, they supported its predecessor Islamic State of Iraq and the Levant. The author shows the funding sources of the Islamic State and assesses the possibilities of its maintenance in near-term. On the ground of this it was drawn an inference that the Russian-Iranian cooperation in the struggle against the Islamic State can lead to victory over this radical organisation. The United States and their allies (partners) in framework of the anti-terrorist coalition cannot do it because they only simulate the struggle.