The article is based on the results of the research project devoted to the role of the parliamentary diplomacy in the modern world politics. The project is realized by the Rethinking Russia and the Russian Center for Promotion of International Initiatives. The article deals with considering the phenomenon of the parliamentary diplomacy, analyzing its nature and sources. Based on observing multisided dynamics of world politics and global trends in the public-government relations, authors define parliamentary diplomacy with the overall context of public diplomacy as quite a relevant mechanism of the modern international communication. The parliamentary aspect is considered as one of the most illustrative and legitimate institutional conjunction of both government (parliament is a constitutional body of power) and public (MPs are representatives of people, of civil society) nature of the modern communication on the mega-political level. Authors also analyze some relevant practical aspects of the Russian parliamentary diplomacy both at bilateral and multilateral levels. Those include parliamentary assemblies of such international organizations as OSCE, CIS, CSTO etc. There is also some focus on parliamentary tracks at the mega-political level for getting over the challenges modern government and its policy face with.