The Russo-Turkish War (1877-1878) was of higher importance not only because it brought an end to most of the Ottoman presence in the Balkans political wise, but also because of its far-reaching consequences for the religious and ethnic communities that co-existed for centuries in the region. During month-long discussions that took place at the Berlin Congress, held in the aftermath of the war, the European Great Powers insisted on extending the clauses of the San Stefano Treaty to the religious groups, exclusively the Christian ones. As a result, the Berlin Treaty included an article on the religious rights and freedom of every newborn Balkan state. Although the specific impact of the war on the Balkan Muslims was not discussed during the Congress, the final clauses brought along the formation of the Islamic Communities - bodies for administrating and managing religious affairs as well as for sustaining indirectly Muslim identity. Despite the fact that this paper does not offer an in-depth analysis due to space limitations, it nevertheless aims to not only critically discuss the dynamics of the foundation process of the Islamic Communities in the Balkans that remain critical religious institutions nowadays, but also to offer and elaborate on several new aspects for future research on this issue. The paper consists of three chapters – first, an overview of the outcome of The Russo-Turkish War and the Berlin Congress is provided, then general discussion topics during the Congress related to religious groups are presented, whereas finally, the paper delves into the concurrent formation of the Islamic Communities in the Balkan states.