The purpose of the article is to explore the modern nature of sectarian tension and to identify the fundamental reasons underlying it. The research involved a number of special methods, in particular, comprehensive systemic and holistic analysis, the method of expert assessment, as well as general scientific methods: analysis, synthesis and comparison. The paper concludes that there are three fundamental reasons among the broad range of reasons engendering sectarian tension that are of foremost importance for the origination of interreligious conflicts, relative to the countries of the Middle East region. The introduction of the fundamental correlation coefficient by the authors made it possible to construct a scale of assessment for individual countries of the Middle East according to the level of tension between the confessions therein and to set the principal measures to attenuate it. The comparison of the fundamental reasons for the emergence of sectarian tension and its manifestation in individual countries made it possible to evaluate the levels of its manifestation. The obtained results will significantly promote the constructive organisation of inter-confessional interaction in the 21st century. © 2022, Ecozone, OAIMDD. All rights reserved.