Ukraine became an independent state in 1991. Nevertheless Russia has disposes of a powerful instrument of influence on its neighbor – the Ukrainian Orthodox Church (Moscow Patriarchate). The UOC (MP) is one the two most important confessions in Ukraine. It opposes the unification of the Eastern Christianity in Ukraine which would contribute to the strengthening of the Ukrainian national identity. On the other hand, it promotes the conception of the “Russkiy mir” affirming the historical and spiritual community of Russia, Ukraine and Belarus. It rejects the plans of Ukraine’s accession to NATO and is critical about the UE. Finally it is an active supporter of the new president Victor Yanukovych, whose first year at the office has been marked by a rapprochement with Russia. The UOC (MP) promotes its ideas through different channels – the clergy, orthodox NGOs, religious newspapers. Its political line enjoys the support of both the Moscow Patriarchate and the Kremlin, which aim at the reintegration of the post-Soviet space. The UOC (MP) could not prosper in Ukraine without political, human, logistic and probably financial support from Russia. The example of the UOC (MP) proves that religion not only remains an important element of national identity, but also can be used as an instrument of influence to shape internal and external policies of other states. It should be therefore taken into account both by the security studies and the IR.