The article aims at investigating the positive impact of Kyrgyz, Armenian, Belorussian and Kazakh diasporas in Russia on the integration within the EAEU. The importance of the research is justified by the fact that the EAEU is one of the most dynamically developing integration groups in the post-soviet space, and diasporas contribute to its developing, though their influence is not widely studied. Diaspora is defined by several characteristics: compound ethnic identity, ethnic migration origin, resistance to assimilation, ties with the country of origin and the country of stay, its own institutions. Diasporas can play both positive and destructive role in the international relations. Elites that have political impact and other diaspora members that establish economic and social ties with the country of origin can be distinguished in a diaspora. Speeches of diasporas' organization leaders, media materials, interviews of diplomats were used as a basis for the investigation into the positive contribution of the diasporas to the Eurasian integration. Kyrgyz diaspora focuses on the resettlement and problems of labour migrants from Kyrgyzstan. Armenian diaspora encourages multilateral forums and economic rapprochement. Belorussian diaspora seems to be more concerned by the developing of the Union State than the EAEU. Kazakh diaspora does not suggest many initiatives in terms of the Eurasian integration. In general, Kyrgyz and Armenian diasporas are the most active. It can be explained by their interest in the integration process and in case of Armenian diaspora by its great historic experience of relations with the country of origin and the country of stay. As for Belorussian diaspora, the Union State seems to be more attractive for it than the EAEU owing to longer history, huge legal framework, a wide range of integration spheres and historic ties with Russia. Kazakh diaspora is less consolidated than the others and does not show a lot of interest in the Eurasian integration. The authorities of the countries of origin and the country of stay do not use the power of diasporas in the integration process to the full extent though.