The Caucasus is perhaps best described as a mosaic of peoples ancient and modern intertwined across a complex, often inaccessible geography that has made it a crossroads linking not only east and west but equally north and south. The aim of this paper is to enhance the understanding of future Iran and Russia challenges in Transcaucasia. Russian post-Soviet geopolitics invokes Eurasianism as its inner rationale and meaning, as a greater good that imbues pragmatic, interest based politics with a sense of mission. Although Russia remains a strong regional power with firm position on international level it is still hard for Moscow to accept loss of the position of great power. The methodology of this research is descriptive-analytical and it attempts to give a geopolitical answer to the question that how Iran can gains a hegemony in the Transcaucasia region?