Abstract. ISIS poses a real threat to security and stability of South-East Asia countries, inspiring local Islamic extremists to conduct jihad for the purpose of creating a pan-regional caliphate "Daulah Islamiyah Nusantara" comprising the territories of Indonesia, Malaysia, Singapore, Brunei, Southern Philippines and Thailand, where the Muslim population exceeds 250 millions. The author assumes that ISIS has potential for increasing its influence on these countries, taking into consideration 1) the presence of long-standing terrorist organizations, which have established contacts with international terrorists, such as Al Qaeda, and are now ready to swear their allegiance to ISIS; 2) the existence of social base – receptive to the ideology of international jihad – that can increase in number in case of engagement of former ISIS fighters from South-East Asia in the battle for the Islamic State creation in the region. This struggle will lead to terror and violence. And strengthening of the ISIS power in the Middle East gives the militants force and determination in achieving this goal. Now the number of the ISIS fighters from South-East Asia exceeds 800 people, but the flow of new supporters can increase, because there is a well-established basis for their recruiting through: preaching in mosques; indoctrination of students in madrasahs and religious boarding schools, funded by radical Islamic organizations; circulating of religious literature of jihad orientation; local radical groups; social networks. To counter the threat of the Islamic community radicalization, the governments rely on the leading Islam organizations and take actions in different directions. But their outcome will depend on whether the Muslim majority of population preserves the inherent religious tolerance.