Formation of myths is the first stage of Society Mythologization. The analyzed in this article myth about inheritance rights of Russia to the Kyivan Rus’1 arose in the 15th century. Recently this myth is being actively spread by the Russian propaganda in the mass media – in particular this is performed through Wikipedia being one of the most attended Internet resources. The purpose of spreading the myth (the second stage of society mythologization) consists in introduction of a certain idea and certain political behavior into the mass consciousness which would at a certain time point influence the process of making the necessary political decision. The third stage of Society Mythologization is represented as spreading the myth in the process of communication between the authorities and citizens. The manipulative function of the political myth has come into action here; the purpose of this myth consists in activation of separatist sentiments of Russian-speaking Ukrainian citizens. Purpose – to explore vulnerability of Wikipedia policy of openness on the basis of a specific example as well as to explore its efficiency for formation of political myths; to analyze the technology used for creation of Wikipedia articles in the process of formation of myths. Methods. Comparison method is applied – texts of Wikipedia articles on various time stages of their creation were compared; results of analyzing Wikipedia pages were correlated to political events of Russian-Ukrainian relations. Formalization technique is applied – representation of the analyzed terms in semiotic and symbolic form; deduction – as a process of drawing a logical conclusion on the basis of the complex of analyzed facts; summarizing. Results. Mythology not obliged to prove anything and Wikipedia aimed at forming the concept and creating only an impression of scientificness and not knowledge as such are perfectly agreed. That is why Wikipedia is one of the most efficient spreaders of myths (first of all political myths) supporting a definite ideology