Mongolian epics were registered in the UNESCO Cultural Heritage List of Humanity, whereat Mongolia has been obliged to study, protect, preserve and develop Mongolian epics. However, no consensus has been reached as to the origin of Mongolian epics in terms of dating, social development phases and space. Therefore, aiming to sketch an outline of these unconcluded questions, we conducted a comparative study on the sources in Mongolian epics such as customs and cultural traits and the archeological finds unearthed in the territory of Mongolia, information data given in the ethnological studies and the ritual implements of Mongolian shamanism. As a result of this study, we proposed a new scientific concept that Mongolian epic was originated in late Bronze Age or 10-4th centuries BCE (3000-2500 years ago) and those who originated and developed Mongolian epics were particularly the owners of deer stone – khirigsuur ad slab burial cultures among the numerous cultures that existed in Mongolia by that period of time. During that period, the owners of deer stones and slab burials inhabited in the vast terrain stretching to Baikal Lake in the north, to In Shan (modern-day Dalan Khar) Mountain, to Dornod great steppes in the east and the Great Lake Depression in the west. Therefore, Mongolian epic was formed in this region, where it was originated on the basis of oral traditions, particularly the shamanic myths and fables; furthermore the shamans were the first epic singers. Receiving reviews from researchers of oral literature, archeologists and historians, the article is prepared for publication.